test: skip mod.rs files when checking for annotations

docs: add J-S-Kim as a contributor for content

.gitignore

@@ -2,3 +2,9 @@
 target/
 **/*.rs.bk
 .DS_Store
+*.pdb
+exercises/clippy/Cargo.toml
+exercises/clippy/Cargo.lock
+.idea
+.vscode
+*.iml

.gitpod.yml

@@ -0,0 +1,7 @@
+tasks:
+  - init: /workspace/rustlings/install.sh
+    command: /workspace/.cargo/bin/rustlings watch
+
+vscode:
+  extensions:
+    - rust-lang.rust@0.7.8:CvNqMTgDdt3UXt+6BCDTVg==

.replit

@@ -0,0 +1,2 @@
+language = "rust"
+run = "[ -x ~/.cargo/bin/rustlings ] && ~/.cargo/bin/rustlings watch || ./install.sh"

.travis.yml

@@ -1,11 +0,0 @@
-language: rust
-rust:
-  - stable
-  - beta
-  - nightly
-script: cargo test --verbose
-matrix:
-  allow_failures:
-    - rust: nightly
-  fast_finish: true
-cache: cargo

AUTHORS.md

@@ -0,0 +1,175 @@
+## Authors
+
+This file lists the people that have contributed to this project.
+
+Excluded from this list are @carols10cents and @diannasoreil, the principal
+authors.
+
+<!-- ALL-CONTRIBUTORS-LIST:START - Do not remove or modify this section -->
+<!-- prettier-ignore-start -->
+<!-- markdownlint-disable -->
+<table>
+  <tr>
+    <td align="center"><a href="http://carol-nichols.com"><img src="https://avatars2.githubusercontent.com/u/193874?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Carol (Nichols &#124;&#124; Goulding)</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=carols10cents" title="Code">💻</a> <a href="#content-carols10cents" title="Content">🖋</a></td>
+    <td align="center"><a href="https://twitter.com/QuietMisdreavus"><img src="https://avatars2.githubusercontent.com/u/5217170?v=4?s=100" width="100px;" alt=""/><br /><sub><b>QuietMisdreavus</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=QuietMisdreavus" title="Code">💻</a> <a href="#content-QuietMisdreavus" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/robertlugg"><img src="https://avatars0.githubusercontent.com/u/6054540?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Robert M Lugg</b></sub></a><br /><a href="#content-robertlugg" title="Content">🖋</a></td>
+    <td align="center"><a href="https://hynek.me/about/"><img src="https://avatars3.githubusercontent.com/u/41240?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Hynek Schlawack</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=hynek" title="Code">💻</a></td>
+    <td align="center"><a href="https://spacekookie.de"><img src="https://avatars0.githubusercontent.com/u/7669898?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Katharina Fey</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=spacekookie" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/lukabavdaz"><img src="https://avatars0.githubusercontent.com/u/9624558?v=4?s=100" width="100px;" alt=""/><br /><sub><b>lukabavdaz</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=lukabavdaz" title="Code">💻</a> <a href="#content-lukabavdaz" title="Content">🖋</a></td>
+    <td align="center"><a href="http://vestera.as"><img src="https://avatars2.githubusercontent.com/u/4187449?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Erik Vesteraas</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=evestera" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/Delet0r"><img src="https://avatars1.githubusercontent.com/u/23195618?v=4?s=100" width="100px;" alt=""/><br /><sub><b>delet0r</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=Delet0r" title="Code">💻</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="http://phinary.ca"><img src="https://avatars1.githubusercontent.com/u/10522375?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Shaun Bennett</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=shaunbennett" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/abagshaw"><img src="https://avatars2.githubusercontent.com/u/8594541?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Andrew Bagshaw</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=abagshaw" title="Code">💻</a></td>
+    <td align="center"><a href="https://ai6ua.net/"><img src="https://avatars2.githubusercontent.com/u/175578?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Kyle Isom</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=kisom" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/ColinPitrat"><img src="https://avatars3.githubusercontent.com/u/1541863?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Colin Pitrat</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=ColinPitrat" title="Code">💻</a></td>
+    <td align="center"><a href="https://zacanger.com"><img src="https://avatars3.githubusercontent.com/u/12520493?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Zac Anger</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=zacanger" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/mgeier"><img src="https://avatars1.githubusercontent.com/u/705404?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Matthias Geier</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=mgeier" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/cjpearce"><img src="https://avatars1.githubusercontent.com/u/3453268?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Chris Pearce</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=cjpearce" title="Code">💻</a></td>
+    <td align="center"><a href="https://yvan-sraka.github.io"><img src="https://avatars2.githubusercontent.com/u/705213?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Yvan Sraka</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=yvan-sraka" title="Code">💻</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="https://github.com/dendi239"><img src="https://avatars3.githubusercontent.com/u/16478650?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Denys Smirnov</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=dendi239" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/eddyp"><img src="https://avatars2.githubusercontent.com/u/123772?v=4?s=100" width="100px;" alt=""/><br /><sub><b>eddyp</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=eddyp" title="Code">💻</a></td>
+    <td align="center"><a href="http://about.me/BrianKung"><img src="https://avatars1.githubusercontent.com/u/2836167?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Brian Kung</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=briankung" title="Code">💻</a> <a href="#content-briankung" title="Content">🖋</a></td>
+    <td align="center"><a href="https://rcousineau.gitlab.io"><img src="https://avatars3.githubusercontent.com/u/281039?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Russell</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=miller-time" title="Code">💻</a></td>
+    <td align="center"><a href="http://danwilhelm.com"><img src="https://avatars3.githubusercontent.com/u/6137185?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Dan Wilhelm</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=danwilhelm" title="Documentation">📖</a></td>
+    <td align="center"><a href="https://github.com/Jesse-Cameron"><img src="https://avatars3.githubusercontent.com/u/3723654?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Jesse</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=Jesse-Cameron" title="Code">💻</a> <a href="#content-Jesse-Cameron" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/MrFroop"><img src="https://avatars3.githubusercontent.com/u/196700?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Fredrik Jambrén</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=MrFroop" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/petemcfarlane"><img src="https://avatars3.githubusercontent.com/u/3472717?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Pete McFarlane</b></sub></a><br /><a href="#content-petemcfarlane" title="Content">🖋</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="https://github.com/nkanderson"><img src="https://avatars0.githubusercontent.com/u/4128825?v=4?s=100" width="100px;" alt=""/><br /><sub><b>nkanderson</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=nkanderson" title="Code">💻</a> <a href="#content-nkanderson" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/ajaxm"><img src="https://avatars0.githubusercontent.com/u/13360138?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ajax M</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=ajaxm" title="Documentation">📖</a></td>
+    <td align="center"><a href="https://dylnuge.com"><img src="https://avatars2.githubusercontent.com/u/118624?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Dylan Nugent</b></sub></a><br /><a href="#content-Dylnuge" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/vyaslav"><img src="https://avatars0.githubusercontent.com/u/1385427?v=4?s=100" width="100px;" alt=""/><br /><sub><b>vyaslav</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=vyaslav" title="Code">💻</a> <a href="#content-vyaslav" title="Content">🖋</a></td>
+    <td align="center"><a href="https://join.sfxd.org"><img src="https://avatars1.githubusercontent.com/u/17297466?v=4?s=100" width="100px;" alt=""/><br /><sub><b>George</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=gdoenlen" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/nyxtom"><img src="https://avatars2.githubusercontent.com/u/222763?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Thomas Holloway</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=nyxtom" title="Code">💻</a> <a href="#content-nyxtom" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/workingjubilee"><img src="https://avatars1.githubusercontent.com/u/46493976?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Jubilee</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=workingjubilee" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/WofWca"><img src="https://avatars1.githubusercontent.com/u/39462442?v=4?s=100" width="100px;" alt=""/><br /><sub><b>WofWca</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=WofWca" title="Code">💻</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="https://github.com/jrvidal"><img src="https://avatars0.githubusercontent.com/u/1636604?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Roberto Vidal</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=jrvidal" title="Code">💻</a> <a href="https://github.com/rust-lang/rustlings/commits?author=jrvidal" title="Documentation">📖</a> <a href="#ideas-jrvidal" title="Ideas, Planning, & Feedback">🤔</a> <a href="#maintenance-jrvidal" title="Maintenance">🚧</a></td>
+    <td align="center"><a href="https://github.com/jensim"><img src="https://avatars0.githubusercontent.com/u/3663856?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Jens</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=jensim" title="Documentation">📖</a></td>
+    <td align="center"><a href="http://rahatah.me/d"><img src="https://avatars3.githubusercontent.com/u/3174006?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Rahat Ahmed</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=rahatarmanahmed" title="Documentation">📖</a></td>
+    <td align="center"><a href="https://github.com/AbdouSeck"><img src="https://avatars2.githubusercontent.com/u/6490055?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Abdou Seck</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=AbdouSeck" title="Code">💻</a> <a href="#content-AbdouSeck" title="Content">🖋</a> <a href="https://github.com/rust-lang/rustlings/pulls?q=is%3Apr+reviewed-by%3AAbdouSeck" title="Reviewed Pull Requests">👀</a></td>
+    <td align="center"><a href="https://codehearts.com"><img src="https://avatars0.githubusercontent.com/u/2885412?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Katie</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=codehearts" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/Socratides"><img src="https://avatars3.githubusercontent.com/u/27732983?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Socrates</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=Socratides" title="Documentation">📖</a></td>
+    <td align="center"><a href="https://github.com/gnodarse"><img src="https://avatars3.githubusercontent.com/u/46761795?v=4?s=100" width="100px;" alt=""/><br /><sub><b>gnodarse</b></sub></a><br /><a href="#content-gnodarse" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/harrisonmetz"><img src="https://avatars1.githubusercontent.com/u/7883408?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Harrison Metzger</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=harrisonmetz" title="Code">💻</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="https://github.com/TorbenJ"><img src="https://avatars2.githubusercontent.com/u/9077102?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Torben Jonas</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=TorbenJ" title="Code">💻</a> <a href="#content-TorbenJ" title="Content">🖋</a></td>
+    <td align="center"><a href="http://paulbissex.com/"><img src="https://avatars0.githubusercontent.com/u/641?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Paul Bissex</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=pbx" title="Documentation">📖</a></td>
+    <td align="center"><a href="https://github.com/sjmann"><img src="https://avatars0.githubusercontent.com/u/6589896?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Steven Mann</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=sjmann" title="Code">💻</a> <a href="#content-sjmann" title="Content">🖋</a></td>
+    <td align="center"><a href="https://smmdb.net/"><img src="https://avatars2.githubusercontent.com/u/5855071?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Mario Reder</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=Tarnadas" title="Code">💻</a> <a href="#content-Tarnadas" title="Content">🖋</a></td>
+    <td align="center"><a href="https://keybase.io/skim"><img src="https://avatars0.githubusercontent.com/u/47347?v=4?s=100" width="100px;" alt=""/><br /><sub><b>skim</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=sl4m" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/sanjaykdragon"><img src="https://avatars1.githubusercontent.com/u/10261698?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Sanjay K</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=sanjaykdragon" title="Code">💻</a> <a href="#content-sanjaykdragon" title="Content">🖋</a></td>
+    <td align="center"><a href="http://www.rohanjain.in"><img src="https://avatars1.githubusercontent.com/u/343499?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Rohan Jain</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=crodjer" title="Code">💻</a></td>
+    <td align="center"><a href="https://www.saidaspen.se"><img src="https://avatars1.githubusercontent.com/u/7727687?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Said Aspen</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=saidaspen" title="Code">💻</a> <a href="#content-saidaspen" title="Content">🖋</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="https://github.com/uce"><img src="https://avatars3.githubusercontent.com/u/1756620?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ufuk Celebi</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=uce" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/lebedevsergey"><img src="https://avatars2.githubusercontent.com/u/7325764?v=4?s=100" width="100px;" alt=""/><br /><sub><b>lebedevsergey</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=lebedevsergey" title="Documentation">📖</a></td>
+    <td align="center"><a href="https://github.com/avrong"><img src="https://avatars2.githubusercontent.com/u/6342851?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Aleksei Trifonov</b></sub></a><br /><a href="#content-avrong" title="Content">🖋</a></td>
+    <td align="center"><a href="https://drn.ie"><img src="https://avatars2.githubusercontent.com/u/411136?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Darren Meehan</b></sub></a><br /><a href="#content-Darrenmeehan" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/jihchi"><img src="https://avatars1.githubusercontent.com/u/87983?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Jihchi Lee</b></sub></a><br /><a href="#content-jihchi" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/bertonha"><img src="https://avatars3.githubusercontent.com/u/1225902?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Christofer Bertonha</b></sub></a><br /><a href="#content-bertonha" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/apatniv"><img src="https://avatars2.githubusercontent.com/u/22565917?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Vivek Bharath Akupatni</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=apatniv" title="Code">💻</a> <a href="https://github.com/rust-lang/rustlings/commits?author=apatniv" title="Tests">⚠️</a></td>
+    <td align="center"><a href="https://github.com/DiD92"><img src="https://avatars3.githubusercontent.com/u/6002416?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Dídac Sementé Fernández</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=DiD92" title="Code">💻</a> <a href="#content-DiD92" title="Content">🖋</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="https://github.com/wrobstory"><img src="https://avatars3.githubusercontent.com/u/2601457?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Rob Story</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=wrobstory" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/siobhanjacobson"><img src="https://avatars2.githubusercontent.com/u/28983835?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Siobhan Jacobson</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=siobhanjacobson" title="Code">💻</a></td>
+    <td align="center"><a href="https://www.linkedin.com/in/evancarroll/"><img src="https://avatars2.githubusercontent.com/u/19922?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Evan Carroll</b></sub></a><br /><a href="#content-EvanCarroll" title="Content">🖋</a></td>
+    <td align="center"><a href="http://www.jawaadmahmood.com"><img src="https://avatars3.githubusercontent.com/u/95606?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Jawaad Mahmood</b></sub></a><br /><a href="#content-jmahmood" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/GaurangTandon"><img src="https://avatars1.githubusercontent.com/u/6308683?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Gaurang Tandon</b></sub></a><br /><a href="#content-GaurangTandon" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/dev-cyprium"><img src="https://avatars1.githubusercontent.com/u/6002628?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Stefan Kupresak</b></sub></a><br /><a href="#content-dev-cyprium" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/greg-el"><img src="https://avatars3.githubusercontent.com/u/45019882?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Greg Leonard</b></sub></a><br /><a href="#content-greg-el" title="Content">🖋</a></td>
+    <td align="center"><a href="https://ryanpcmcquen.org"><img src="https://avatars3.githubusercontent.com/u/772937?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ryan McQuen</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=ryanpcmcquen" title="Code">💻</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="https://github.com/AnnikaCodes"><img src="https://avatars3.githubusercontent.com/u/56906084?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Annika</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/pulls?q=is%3Apr+reviewed-by%3AAnnikaCodes" title="Reviewed Pull Requests">👀</a></td>
+    <td align="center"><a href="https://darnuria.eu"><img src="https://avatars1.githubusercontent.com/u/2827553?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Axel Viala</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=darnuria" title="Code">💻</a></td>
+    <td align="center"><a href="https://sazid.github.io"><img src="https://avatars1.githubusercontent.com/u/2370167?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Mohammed Sazid Al Rashid</b></sub></a><br /><a href="#content-sazid" title="Content">🖋</a> <a href="https://github.com/rust-lang/rustlings/commits?author=sazid" title="Code">💻</a></td>
+    <td align="center"><a href="https://codingthemsoftly.com"><img src="https://avatars1.githubusercontent.com/u/17479099?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Caleb Webber</b></sub></a><br /><a href="#maintenance-seeplusplus" title="Maintenance">🚧</a></td>
+    <td align="center"><a href="https://github.com/pcn"><img src="https://avatars2.githubusercontent.com/u/1056756?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Peter N</b></sub></a><br /><a href="#maintenance-pcn" title="Maintenance">🚧</a></td>
+    <td align="center"><a href="https://github.com/seancad"><img src="https://avatars1.githubusercontent.com/u/47405611?v=4?s=100" width="100px;" alt=""/><br /><sub><b>seancad</b></sub></a><br /><a href="#maintenance-seancad" title="Maintenance">🚧</a></td>
+    <td align="center"><a href="http://willhayworth.com"><img src="https://avatars3.githubusercontent.com/u/181174?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Will Hayworth</b></sub></a><br /><a href="#content-wsh" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/chrizel"><img src="https://avatars3.githubusercontent.com/u/20802?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Christian Zeller</b></sub></a><br /><a href="#content-chrizel" title="Content">🖋</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="https://github.com/jfchevrette"><img src="https://avatars.githubusercontent.com/u/3001?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Jean-Francois Chevrette</b></sub></a><br /><a href="#content-jfchevrette" title="Content">🖋</a> <a href="https://github.com/rust-lang/rustlings/commits?author=jfchevrette" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/jbaber"><img src="https://avatars.githubusercontent.com/u/1908117?v=4?s=100" width="100px;" alt=""/><br /><sub><b>John Baber-Lucero</b></sub></a><br /><a href="#content-jbaber" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/tal-zvon"><img src="https://avatars.githubusercontent.com/u/3195851?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Tal</b></sub></a><br /><a href="#content-tal-zvon" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/apogeeoak"><img src="https://avatars.githubusercontent.com/u/59737221?v=4?s=100" width="100px;" alt=""/><br /><sub><b>apogeeoak</b></sub></a><br /><a href="#content-apogeeoak" title="Content">🖋</a> <a href="https://github.com/rust-lang/rustlings/commits?author=apogeeoak" title="Code">💻</a></td>
+    <td align="center"><a href="http://www.garfieldtech.com/"><img src="https://avatars.githubusercontent.com/u/254863?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Larry Garfield</b></sub></a><br /><a href="#content-Crell" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/circumspect"><img src="https://avatars.githubusercontent.com/u/40770208?v=4?s=100" width="100px;" alt=""/><br /><sub><b>circumspect</b></sub></a><br /><a href="#content-circumspect" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/cjwyett"><img src="https://avatars.githubusercontent.com/u/34195737?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Cyrus Wyett</b></sub></a><br /><a href="#content-cjwyett" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/cadolphs"><img src="https://avatars.githubusercontent.com/u/13894820?v=4?s=100" width="100px;" alt=""/><br /><sub><b>cadolphs</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=cadolphs" title="Code">💻</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="https://www.haveneer.com"><img src="https://avatars.githubusercontent.com/u/26146722?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Pascal H.</b></sub></a><br /><a href="#content-hpwxf" title="Content">🖋</a></td>
+    <td align="center"><a href="https://twitter.com/chapeupreto"><img src="https://avatars.githubusercontent.com/u/834048?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Rod Elias</b></sub></a><br /><a href="#content-chapeupreto" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/blerchy"><img src="https://avatars.githubusercontent.com/u/2555355?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Matt Lebl</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=blerchy" title="Code">💻</a></td>
+    <td align="center"><a href="http://flakolefluk.dev"><img src="https://avatars.githubusercontent.com/u/11986564?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ignacio Le Fluk</b></sub></a><br /><a href="#content-flakolefluk" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/tlyu"><img src="https://avatars.githubusercontent.com/u/431873?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Taylor Yu</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=tlyu" title="Code">💻</a> <a href="#content-tlyu" title="Content">🖋</a></td>
+    <td align="center"><a href="https://zerotask.github.io"><img src="https://avatars.githubusercontent.com/u/20150243?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Patrick Hintermayer</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=Zerotask" title="Code">💻</a></td>
+    <td align="center"><a href="https://petkopavlovski.com/"><img src="https://avatars.githubusercontent.com/u/32264020?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Pete Pavlovski</b></sub></a><br /><a href="#content-arthas168" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/k12ish"><img src="https://avatars.githubusercontent.com/u/45272873?v=4?s=100" width="100px;" alt=""/><br /><sub><b>k12ish</b></sub></a><br /><a href="#content-k12ish" title="Content">🖋</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="https://github.com/hongshaoyang"><img src="https://avatars.githubusercontent.com/u/19281800?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Shao Yang Hong</b></sub></a><br /><a href="#content-hongshaoyang" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/bmacer"><img src="https://avatars.githubusercontent.com/u/13931806?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Brandon Macer</b></sub></a><br /><a href="#content-bmacer" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/stoiandan"><img src="https://avatars.githubusercontent.com/u/10388612?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Stoian Dan</b></sub></a><br /><a href="#content-stoiandan" title="Content">🖋</a></td>
+    <td align="center"><a href="https://about.me/pjdelport"><img src="https://avatars.githubusercontent.com/u/630271?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Pi Delport</b></sub></a><br /><a href="#content-PiDelport" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/sateeshkumarb"><img src="https://avatars.githubusercontent.com/u/429263?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Sateesh </b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=sateeshkumarb" title="Code">💻</a> <a href="#content-sateeshkumarb" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/kayuapi"><img src="https://avatars.githubusercontent.com/u/10304328?v=4?s=100" width="100px;" alt=""/><br /><sub><b>ZC</b></sub></a><br /><a href="#content-kayuapi" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/hyperparabolic"><img src="https://avatars.githubusercontent.com/u/12348474?v=4?s=100" width="100px;" alt=""/><br /><sub><b>hyperparabolic</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=hyperparabolic" title="Code">💻</a></td>
+    <td align="center"><a href="https://www.net4visions.at"><img src="https://avatars.githubusercontent.com/u/5228369?v=4?s=100" width="100px;" alt=""/><br /><sub><b>arlecchino</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=kolbma" title="Documentation">📖</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="https://richthofen.io/"><img src="https://avatars.githubusercontent.com/u/7576730?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Richthofen</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=jazzplato" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/cseltol"><img src="https://avatars.githubusercontent.com/u/64264529?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ivan Nerazumov</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=cseltol" title="Documentation">📖</a></td>
+    <td align="center"><a href="https://github.com/lauralindzey"><img src="https://avatars.githubusercontent.com/u/65185744?v=4?s=100" width="100px;" alt=""/><br /><sub><b>lauralindzey</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=lauralindzey" title="Documentation">📖</a></td>
+    <td align="center"><a href="https://github.com/sinharaksh1t"><img src="https://avatars.githubusercontent.com/u/28585848?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Rakshit Sinha</b></sub></a><br /><a href="#content-sinharaksh1t" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/dbednar230"><img src="https://avatars.githubusercontent.com/u/54457902?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Damian</b></sub></a><br /><a href="#content-dbednar230" title="Content">🖋</a></td>
+    <td align="center"><a href="https://benarmstead.co.uk"><img src="https://avatars.githubusercontent.com/u/70973680?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ben Armstead</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=benarmstead" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/anuk909"><img src="https://avatars.githubusercontent.com/u/34924662?v=4?s=100" width="100px;" alt=""/><br /><sub><b>anuk909</b></sub></a><br /><a href="#content-anuk909" title="Content">🖋</a> <a href="https://github.com/rust-lang/rustlings/commits?author=anuk909" title="Code">💻</a></td>
+    <td align="center"><a href="https://granddaifuku.com/"><img src="https://avatars.githubusercontent.com/u/49578068?v=4?s=100" width="100px;" alt=""/><br /><sub><b>granddaifuku</b></sub></a><br /><a href="#content-granddaifuku" title="Content">🖋</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="https://weilet.me"><img src="https://avatars.githubusercontent.com/u/32561597?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Weilet</b></sub></a><br /><a href="#content-Weilet" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/Millione"><img src="https://avatars.githubusercontent.com/u/38575932?v=4?s=100" width="100px;" alt=""/><br /><sub><b>LIU JIE</b></sub></a><br /><a href="#content-Millione" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/abusch"><img src="https://avatars.githubusercontent.com/u/506344?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Antoine Büsch</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=abusch" title="Code">💻</a></td>
+    <td align="center"><a href="https://frogtd.com/"><img src="https://avatars.githubusercontent.com/u/31412003?v=4?s=100" width="100px;" alt=""/><br /><sub><b>frogtd</b></sub></a><br /><a href="#content-frogtd" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/EmisonLu"><img src="https://avatars.githubusercontent.com/u/54395432?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Zhenghao Lu</b></sub></a><br /><a href="#content-EmisonLu" title="Content">🖋</a></td>
+    <td align="center"><a href="https://soundtrackyourbrand.com"><img src="https://avatars.githubusercontent.com/u/762956?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Fredrik Enestad</b></sub></a><br /><a href="#content-fredr" title="Content">🖋</a></td>
+    <td align="center"><a href="http://xuesong.pydevops.com"><img src="https://avatars.githubusercontent.com/u/18476085?v=4?s=100" width="100px;" alt=""/><br /><sub><b>xuesong</b></sub></a><br /><a href="#content-xuesongbj" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/MpdWalsh"><img src="https://avatars.githubusercontent.com/u/48160144?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Michael Walsh</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=MpdWalsh" title="Code">💻</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="https://github.com/alirezaghey"><img src="https://avatars.githubusercontent.com/u/26653424?v=4?s=100" width="100px;" alt=""/><br /><sub><b>alirezaghey</b></sub></a><br /><a href="#content-alirezaghey" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/frvannes16"><img src="https://avatars.githubusercontent.com/u/3188475?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Franklin van Nes</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=frvannes16" title="Code">💻</a></td>
+    <td align="center"><a href="https://nekonako.github.io"><img src="https://avatars.githubusercontent.com/u/46141275?v=4?s=100" width="100px;" alt=""/><br /><sub><b>nekonako</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=nekonako" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/tan-zx"><img src="https://avatars.githubusercontent.com/u/67887489?v=4?s=100" width="100px;" alt=""/><br /><sub><b>ZX</b></sub></a><br /><a href="#content-tan-zx" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/sundevilyang"><img src="https://avatars.githubusercontent.com/u/1499214?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Yang Wen</b></sub></a><br /><a href="#content-sundevilyang" title="Content">🖋</a></td>
+    <td align="center"><a href="https://brandon-high.com"><img src="https://avatars.githubusercontent.com/u/759848?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Brandon High</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=highb" title="Documentation">📖</a></td>
+    <td align="center"><a href="https://github.com/x-hgg-x"><img src="https://avatars.githubusercontent.com/u/39058530?v=4?s=100" width="100px;" alt=""/><br /><sub><b>x-hgg-x</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=x-hgg-x" title="Code">💻</a></td>
+    <td align="center"><a href="http://kisaragieffective.github.io"><img src="https://avatars.githubusercontent.com/u/48310258?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Kisaragi</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=KisaragiEffective" title="Documentation">📖</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="https://github.com/Kallu-A"><img src="https://avatars.githubusercontent.com/u/73198738?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Lucas Aries</b></sub></a><br /><a href="#content-Kallu-A" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/ragreenburg"><img src="https://avatars.githubusercontent.com/u/24358100?v=4?s=100" width="100px;" alt=""/><br /><sub><b>ragreenburg</b></sub></a><br /><a href="#content-ragreenburg" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/stevenfukase"><img src="https://avatars.githubusercontent.com/u/66785624?v=4?s=100" width="100px;" alt=""/><br /><sub><b>stevenfukase</b></sub></a><br /><a href="#content-stevenfukase" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/J-S-Kim"><img src="https://avatars.githubusercontent.com/u/17569303?v=4?s=100" width="100px;" alt=""/><br /><sub><b>J-S-Kim</b></sub></a><br /><a href="#content-J-S-Kim" title="Content">🖋</a></td>
+  </tr>
+</table>
+
+<!-- markdownlint-restore -->
+<!-- prettier-ignore-end -->
+
+<!-- ALL-CONTRIBUTORS-LIST:END -->
+
+This project follows the [all-contributors](https://github.com/all-contributors/all-contributors) specification. Contributions of any kind welcome!

CHANGELOG.md

@@ -1,3 +1,332 @@
+<a name="4.7.0"></a>
+## 4.7.0 (2022-04-14)
+
+
+#### Features
+
+*   Add move_semantics6.rs exercise (#908) ([3f0e1303](https://github.com/rust-lang/rustlings/commit/3f0e1303e0b3bf3fecc0baced3c8b8a37f83c184))
+* **intro:**  Add intro section. ([21c9f441](https://github.com/rust-lang/rustlings/commit/21c9f44168394e08338fd470b5f49b1fd235986f))
+* Include exercises folder in the project structure behind a feature, enabling rust-analyzer to work (#917) ([179a75a6](https://github.com/rust-lang/rustlings/commit/179a75a68d03ac9518dec2297fb17f91a4fc506b))
+
+#### Bug Fixes
+
+* Fix a few spelling mistakes ([1c0fe3cb](https://github.com/rust-lang/rustlings/commit/1c0fe3cbcca85f90b3985985b8e265ee872a2ab2))
+* **cli:**
+  * Move long text strings into constants. ([f78c4802](https://github.com/rust-lang/rustlings/commit/f78c48020830d7900dd8d81f355606581670446d))
+  * Replace `filter_map()` with `find_map()` ([9b27e8d](https://github.com/rust-lang/rustlings/commit/9b27e8d993ca20232fe38a412750c3f845a83b65))
+* **clippy1:**
+  *  Set clippy::float_cmp lint to deny (#907) ([71a06044](https://github.com/rust-lang/rustlings/commit/71a06044e6a96ff756dc31d7b0ed665ae4badb57))
+  *  Updated code to test correctness clippy lint with approx_constant lint rule ([f2650de3](https://github.com/rust-lang/rustlings/commit/f2650de369810867d2763e935ac0963c32ec420e))
+* **errors1:**
+  * Add a comment to make the purpose more clear (#486) ([cbcde345](https://github.com/rust-lang/rustlings/commit/cbcde345409c3e550112e449242848eaa3391bb6))
+  * Don't modify tests (#958) ([60bb7cc](https://github.com/rust-lang/rustlings/commit/60bb7cc3931d21d3986ad52b2b302e632a93831c))
+* **errors6:** Remove existing answer code ([43d0623](https://github.com/rust-lang/rustlings/commit/43d0623086edbc46fe896ba59c7afa22c3da9f7a))
+* **functions5:**  Remove wrong new line and small English improvements (#885) ([8ef4869b](https://github.com/rust-lang/rustlings/commit/8ef4869b264094e5a9b50452b4534823a9df19c3))
+* **install:**  protect path with whitespaces using quotes and stop at the first error ([d114847f](https://github.com/rust-lang/rustlings/commit/d114847f256c5f571c0b4c87e04b04bce3435509))
+* **intro1:**  Add compiler error explanation. ([9b8de655](https://github.com/rust-lang/rustlings/commit/9b8de65525a5576b78cf0c8e4098cdd34296338f))
+* **iterators1:**  reorder TODO steps ([0bd7a063](https://github.com/rust-lang/rustlings/commit/0bd7a0631a17a9d69af5746795a30efc9cf64e6e))
+* **move_semantics2:**  Add comment ([89650f80](https://github.com/rust-lang/rustlings/commit/89650f808af23a32c9a2c6d46592b77547a6a464))
+* **move_semantics5:**  correct typo (#857) ([46c28d5c](https://github.com/rust-lang/rustlings/commit/46c28d5cef3d8446b5a356b19d8dbc725f91a3a0))
+* **quiz1:**  update to say quiz covers "If" ([1622e8c1](https://github.com/rust-lang/rustlings/commit/1622e8c198d89739765c915203efff0091bdeb78))
+* **structs3:**
+  * Add a hint for panic (#608) ([4f7ff5d9](https://github.com/rust-lang/rustlings/commit/4f7ff5d9c7b2d8b045194c1a9469d37e30257c4a))
+  * remove redundant 'return' (#852) ([bf33829d](https://github.com/rust-lang/rustlings/commit/bf33829da240375d086f96267fc2e02fa6b07001))
+  * Assigned value to `cents_per_gram` in test ([d1ee2da](https://github.com/rust-lang/rustlings/commit/d1ee2daf14f19105e6db3f9c610f44293d688532))
+* **structs3.rs:**  assigned value to cents_per_gram in test ([d1ee2daf](https://github.com/rust-lang/rustlings/commit/d1ee2daf14f19105e6db3f9c610f44293d688532))
+* **traits1:**  rename test functions to snake case (#854) ([1663a16e](https://github.com/rust-lang/rustlings/commit/1663a16eade6ca646b6ed061735f7982434d530d))
+
+#### Documentation improvements
+
+* Add hints on how to get GCC installed (#741) ([bc56861](https://github.com/rust-lang/rustlings/commit/bc5686174463ad6f4f6b824b0e9b97c3039d4886))
+* Fix some code blocks that were not highlighted ([17f9d74](https://github.com/rust-lang/rustlings/commit/17f9d7429ccd133a72e815fb5618e0ce79560929))
+
+
+<a name="4.6.0"></a>
+## 4.6.0 (2021-09-25)
+
+
+#### Features
+
+*   add advanced_errs2 ([abd6b70c](https://github.com/rust-lang/rustlings/commit/abd6b70c72dc6426752ff41f09160b839e5c449e))
+*   add advanced_errs1 ([882d535b](https://github.com/rust-lang/rustlings/commit/882d535ba8628d5e0b37e8664b3e2f26260b2671))
+*   Add a farewell message when quitting `watch` ([1caef0b4](https://github.com/rust-lang/rustlings/commit/1caef0b43494c8b8cdd6c9260147e70d510f1aca))
+*   add more watch commands ([a7dc080b](https://github.com/rust-lang/rustlings/commit/a7dc080b95e49146fbaafe6922a6de2f8cb1582a), closes [#842](https://github.com/rust-lang/rustlings/issues/842))
+* **modules:**  update exercises, add modules3 (#822) ([dfd2fab4](https://github.com/rust-lang/rustlings/commit/dfd2fab4f33d1bf59e2e5ee03123c0c9a67a9481))
+* **quiz1:**  add default function name in comment (#838) ([0a11bad7](https://github.com/rust-lang/rustlings/commit/0a11bad71402b5403143d642f439f57931278c07))
+
+#### Bug Fixes
+
+*   Correct small typo in exercises/conversions/from_str.rs ([86cc8529](https://github.com/rust-lang/rustlings/commit/86cc85295ae36948963ae52882e285d7e3e29323))
+* **cli:**  typo in exercise.rs (#848) ([06d5c097](https://github.com/rust-lang/rustlings/commit/06d5c0973a3dffa3c6c6f70acb775d4c6630323c))
+* **from_str, try_from_into:**  custom error types ([2dc93cad](https://github.com/rust-lang/rustlings/commit/2dc93caddad43821743e4903d89b355df58d7a49))
+* **modules2:**  fix typo (#835) ([1c3beb0a](https://github.com/rust-lang/rustlings/commit/1c3beb0a59178c950dc05fe8ee2346b017429ae0))
+* **move_semantics5:**
+  *  change &mut *y to &mut x (#814) ([d75759e8](https://github.com/rust-lang/rustlings/commit/d75759e829fdcd64ef071cf4b6eae2a011a7718b))
+  *  Clarify instructions ([df25684c](https://github.com/rust-lang/rustlings/commit/df25684cb79f8413915e00b5efef29369849cef1))
+* **quiz1:**  Fix inconsistent wording (#826) ([03131a3d](https://github.com/rust-lang/rustlings/commit/03131a3d35d9842598150f9da817f7cc26e2669a))
+
+
+
+<a name="4.5.0"></a>
+## 4.5.0 (2021-07-07)
+
+
+#### Features
+
+*   Add move_semantics5 exercise. (#746) ([399ab328](https://github.com/rust-lang/rustlings/commit/399ab328d8d407265c09563aa4ef4534b2503ff2))
+* **cli:**  Add "next" to run the next unsolved exercise. (#785) ([d20e413a](https://github.com/rust-lang/rustlings/commit/d20e413a68772cd493561f2651cf244e822b7ca5))
+
+#### Bug Fixes
+
+*   rename result1 to errors4 ([50ab289d](https://github.com/rust-lang/rustlings/commit/50ab289da6b9eb19a7486c341b00048c516b88c0))
+*   move_semantics5 hints ([1b858285](https://github.com/rust-lang/rustlings/commit/1b85828548f46f58b622b5e0c00f8c989f928807))
+*   remove trailing whitespaces from iterators1 ([4d4fa774](https://github.com/rust-lang/rustlings/commit/4d4fa77459392acd3581c6068aa8be9a02de12fc))
+*   add hints to generics1 and generics2 exercises ([31457940](https://github.com/rust-lang/rustlings/commit/31457940846b3844d78d4a4d2b074bc8d6aaf1eb))
+*   remove trailing whitespace ([d9b69bd1](https://github.com/rust-lang/rustlings/commit/d9b69bd1a0a7a99f2c0d80933ad2eea44c8c71b2))
+* **installation:**  first PowerShell command ([aa9a943d](https://github.com/rust-lang/rustlings/commit/aa9a943ddf3ae260782e73c26bcc9db60e5894b6))
+* **iterators5:**  derive Clone, Copy ([91fc9e31](https://github.com/rust-lang/rustlings/commit/91fc9e3118f4af603c9911698cc2a234725cb032))
+* **quiz1:**  Updated question description (#794) ([d8766496](https://github.com/rust-lang/rustlings/commit/d876649616cc8a8dd5f539f8bc1a5434b960b1e9))
+* **try_from_into, from_str:**  hints for dyn Error ([11d2cf0d](https://github.com/rust-lang/rustlings/commit/11d2cf0d604dee3f5023c17802d69438e69fa50e))
+* **variables5:**  confine the answer further ([48ffcbd2](https://github.com/rust-lang/rustlings/commit/48ffcbd2c4cc4d936c2c7480019190f179813cc5))
+
+
+
+<a name="4.4.0"></a>
+## 4.4.0 (2021-04-24)
+
+
+#### Bug Fixes
+
+*   Fix spelling error in main.rs ([91ee27f2](https://github.com/rust-lang/rustlings/commit/91ee27f22bd3797a9db57e5fd430801c170c5db8))
+*   typo in default out text ([644c49f1](https://github.com/rust-lang/rustlings/commit/644c49f1e04cbb24e95872b3a52b07d692ae3bc8))
+* **collections:**  Naming exercises for vectors and hashmap ([bef39b12](https://github.com/rust-lang/rustlings/commit/bef39b125961310b34b34871e480a82e82af4678))
+* **from_str:**
+  *  Correct typos ([5f7c89f8](https://github.com/rust-lang/rustlings/commit/5f7c89f85db1f33da01911eaa479c3a2d4721678))
+  *  test for error instead of unwrap/should_panic ([15e71535](https://github.com/rust-lang/rustlings/commit/15e71535f37cfaed36e22eb778728d186e2104ab))
+  *   use trait objects for from_str ([c3e7b831](https://github.com/rust-lang/rustlings/commit/c3e7b831786c9172ed8bd5d150f3c432f242fba9))
+* **functions3:**  improve function argument type (#687) ([a6509cc4](https://github.com/rust-lang/rustlings/commit/a6509cc4d545d8825f01ddf7ee37823b372154dd))
+* **hashmap2:**  Update incorrect assertion (#660) ([72aaa15e](https://github.com/rust-lang/rustlings/commit/72aaa15e6ab4b72b3422f1c6356396e20a2a2bb8))
+* **info:**  Fix typo (#635) ([cddc1e86](https://github.com/rust-lang/rustlings/commit/cddc1e86e7ec744ee644cc774a4887b1a0ded3e8))
+* **iterators2:**  Moved errors out of tests. ([baf4ba17](https://github.com/rust-lang/rustlings/commit/baf4ba175ba6eb92989e3dd54ecbec4bedc9a863), closes [#359](https://github.com/rust-lang/rustlings/issues/359))
+* **iterators3:**  Enabled iterators3.rs to run without commented out tests. ([c6712dfc](https://github.com/rust-lang/rustlings/commit/c6712dfccd1a093e590ad22bbc4f49edc417dac0))
+* **main:**  Let find_exercise work with borrows ([347f30bd](https://github.com/rust-lang/rustlings/commit/347f30bd867343c5ace1097e085a1f7e356553f7))
+* **move_semantics4:**
+  *  Remove redundant "instead" (#640) ([cc266d7d](https://github.com/rust-lang/rustlings/commit/cc266d7d80b91e79df3f61984f231b7f1587218e))
+  *  Small readbility improvement (#617) ([10965920](https://github.com/rust-lang/rustlings/commit/10965920fbdf8a1efc85bed869e55a1787006404))
+* **option2:**  Rename uninformative variables (#675) ([b4de6594](https://github.com/rust-lang/rustlings/commit/b4de6594380636817d13c2677ec6f472a964cf43))
+* **quiz3:**  Force an answer to Q2 (#672) ([0d894e6f](https://github.com/rust-lang/rustlings/commit/0d894e6ff739943901e1ae8c904582e5c2f843bd))
+* **structs:**  Add 5.3 to structs/README (#652) ([6bd791f2](https://github.com/rust-lang/rustlings/commit/6bd791f2f44aa7f0ad926df767f6b1fa8f12a9a9))
+* **structs2:**  correct grammar in hint (#663) ([ebdb66c7](https://github.com/rust-lang/rustlings/commit/ebdb66c7bfb6d687a14cc511a559a222e6fc5de4))
+* **structs3:**
+  * reword heading comment (#664) ([9f3e8c2d](https://github.com/rust-lang/rustlings/commit/9f3e8c2dde645e5264c2d2200e68842b5f47bfa3))
+  *   add check to prevent naive implementation of is_international ([05a753fe](https://github.com/rust-lang/rustlings/commit/05a753fe6333d36dbee5f68c21dec04eacdc75df))
+* **threads1:**  line number correction ([7857b0a6](https://github.com/rust-lang/rustlings/commit/7857b0a689b0847f48d8c14cbd1865e3b812d5ca))
+* **try_from_into:**  use trait objects ([2e93a588](https://github.com/rust-lang/rustlings/commit/2e93a588e0abe8badb7eafafb9e7d073c2be5df8))
+
+#### Features
+
+*   Replace clap with argh ([7928122f](https://github.com/rust-lang/rustlings/commit/7928122fcef9ca7834d988b1ec8ca0687478beeb))
+*   Replace emojis when NO_EMOJI env variable present ([8d62a996](https://github.com/rust-lang/rustlings/commit/8d62a9963708dbecd9312e8bcc4b47049c72d155))
+*   Added iterators5.rs exercise. ([b29ea17e](https://github.com/rust-lang/rustlings/commit/b29ea17ea94d1862114af2cf5ced0e09c197dc35))
+* **arc1:**  Add more details to description and hint (#710) ([81be4044](https://github.com/rust-lang/rustlings/commit/81be40448777fa338ebced3b0bfc1b32d6370313))
+* **cli:**  Improve the list command with options, and then some ([8bbe4ff1](https://github.com/rust-lang/rustlings/commit/8bbe4ff1385c5c169c90cd3ff9253f9a91daaf8e))
+* **list:**
+  *  updated progress percentage ([1c6f7e4b](https://github.com/rust-lang/rustlings/commit/1c6f7e4b7b9b3bd36f4da2bb2b69c549cc8bd913))
+  *  added progress info ([c0e3daac](https://github.com/rust-lang/rustlings/commit/c0e3daacaf6850811df5bc57fa43e0f249d5cfa4))
+
+
+
+<a name="4.3.0"></a>
+## 4.3.0 (2020-12-29)
+
+#### Features
+
+*   Rewrite default out text ([44d39112](https://github.com/rust-lang/rustlings/commit/44d39112ff122b29c9793fe52e605df1612c6490))
+*   match exercise order to book chapters (#541) ([033bf119](https://github.com/rust-lang/rustlings/commit/033bf1198fc8bfce1b570e49da7cde010aa552e3))
+*   Crab? (#586) ([fa9f522b](https://github.com/rust-lang/rustlings/commit/fa9f522b7f043d7ef73a39f003a9272dfe72c4f4))
+*   add "rustlings list" command ([838f9f30](https://github.com/rust-lang/rustlings/commit/838f9f30083d0b23fd67503dcf0fbeca498e6647))
+* **try_from_into:**  remove duplicate annotation ([04f1d079](https://github.com/rust-lang/rustlings/commit/04f1d079aa42a2f49af694bc92c67d731d31a53f))
+
+#### Bug Fixes
+
+*   update structs README ([bcf14cf6](https://github.com/rust-lang/rustlings/commit/bcf14cf677adb3a38a3ac3ca53f3c69f61153025))
+*   added missing exercises to info.toml ([90cfb6ff](https://github.com/rust-lang/rustlings/commit/90cfb6ff28377531bfc34acb70547bdb13374f6b))
+*   gives a bit more context to magic number ([30644c9a](https://github.com/rust-lang/rustlings/commit/30644c9a062b825c0ea89435dc59f0cad86b110e))
+* **functions2:**  Change signature to trigger precise error message: (#605) ([0ef95947](https://github.com/rust-lang/rustlings/commit/0ef95947cc30482e63a7045be6cc2fb6f6dcb4cc))
+* **structs1:**  Adjust wording (#573) ([9334783d](https://github.com/rust-lang/rustlings/commit/9334783da31d821cc59174fbe8320df95828926c))
+* **try_from_into:**
+  *  type error ([4f4cfcf3](https://github.com/rust-lang/rustlings/commit/4f4cfcf3c36c8718c7c170c9c3a6935e6ef0618c))
+  *  Update description (#584) ([96347df9](https://github.com/rust-lang/rustlings/commit/96347df9df294f01153b29d9ad4ba361f665c755))
+* **vec1:**  Have test compare every element in a and v ([9b6c6293](https://github.com/rust-lang/rustlings/commit/9b6c629397b24b944f484f5b2bbd8144266b5695))
+
+<a name="4.2.0"></a>
+## 4.2.0 (2020-11-07)
+
+#### Features
+
+*   Add HashMap exercises ([633c00cf](https://github.com/rust-lang/rustlings/commit/633c00cf8071e1e82959a3010452a32f34f29fc9))
+*   Add Vec exercises ([0c12fa31](https://github.com/rust-lang/rustlings/commit/0c12fa31c57c03c6287458a0a8aca7afd057baf6))
+* **primitive_types6:**  Add a test (#548) ([2b1fb2b7](https://github.com/rust-lang/rustlings/commit/2b1fb2b739bf9ad8d6b7b12af25fee173011bfc4))
+* **try_from_into:**  Add tests (#571) ([95ccd926](https://github.com/rust-lang/rustlings/commit/95ccd92616ae79ba287cce221101e0bbe4f68cdc))
+
+#### Bug Fixes
+
+*   log error output when inotify limit is exceeded ([d61b4e5a](https://github.com/rust-lang/rustlings/commit/d61b4e5a13b44d72d004082f523fa1b6b24c1aca))
+*   more unique temp_file ([5643ef05](https://github.com/rust-lang/rustlings/commit/5643ef05bc81e4a840e9456f4406a769abbe1392))
+* **installation:**  Update the MinRustVersion ([21bfb2d4](https://github.com/rust-lang/rustlings/commit/21bfb2d4777429c87d8d3b5fbf0ce66006dcd034))
+* **iterators2:**  Update description (#578) ([197d3a3d](https://github.com/rust-lang/rustlings/commit/197d3a3d8961b2465579218a6749b2b2cefa8ddd))
+* **primitive_types6:**
+  *  remove 'unused doc comment' warning ([472d8592](https://github.com/rust-lang/rustlings/commit/472d8592d65c8275332a20dfc269e7ac0d41bc88))
+  *  missing comma in test ([4fb230da](https://github.com/rust-lang/rustlings/commit/4fb230daf1251444fcf29e085cee222a91f8a37e))
+* **quiz3:**  Second test is for odd numbers, not even. (#553) ([18e0bfef](https://github.com/rust-lang/rustlings/commit/18e0bfef1de53071e353ba1ec5837002ff7290e6))
+
+<a name="4.1.0"></a>
+## 4.1.0 (2020-10-05)
+
+#### Bug Fixes
+
+*   Update rustlings version in Cargo.lock ([1cc40bc9](https://github.com/rust-lang/rustlings/commit/1cc40bc9ce95c23d56f6d91fa1c4deb646231fef))
+* **arc1:**  index mod should equal thread count ([b4062ef6](https://github.com/rust-lang/rustlings/commit/b4062ef6993e80dac107c4093ea85166ad3ee0fa))
+* **enums3:**  Update Message::ChangeColor to take a tuple. (#457) ([4b6540c7](https://github.com/rust-lang/rustlings/commit/4b6540c71adabad647de8a09e57295e7c7c7d794))
+* **exercises:**  adding question mark to quiz2 ([101072ab](https://github.com/rust-lang/rustlings/commit/101072ab9f8c80b40b8b88cb06cbe38aca2481c5))
+* **generics3:**  clarify grade change ([47f7672c](https://github.com/rust-lang/rustlings/commit/47f7672c0307732056e7426e81d351f0dd7e22e5))
+* **structs3:**  Small adjustment of variable name ([114b54cb](https://github.com/rust-lang/rustlings/commit/114b54cbdb977234b39e5f180d937c14c78bb8b2))
+* **using_as:**  Add test so that proper type is returned. (#512) ([3286c5ec](https://github.com/rust-lang/rustlings/commit/3286c5ec19ea5fb7ded81d047da5f8594108a490))
+
+#### Features
+
+*   Added iterators1.rs exercise ([9642f5a3](https://github.com/rust-lang/rustlings/commit/9642f5a3f686270a4f8f6ba969919ddbbc4f7fdd))
+*   Add ability to run rustlings on repl.it (#471) ([8f7b5bd0](https://github.com/rust-lang/rustlings/commit/8f7b5bd00eb83542b959830ef55192d2d76db90a))
+*   Add gitpod support (#473) ([4821a8be](https://github.com/rust-lang/rustlings/commit/4821a8be94af4f669042a06ab917934cfacd032f))
+*   Remind the user of the hint option (#425) ([816b1f5e](https://github.com/rust-lang/rustlings/commit/816b1f5e85d6cc6e72673813a85d0ada2a8f84af))
+*   Remind the user of the hint option (#425) ([9f61db5d](https://github.com/rust-lang/rustlings/commit/9f61db5dbe38538cf06571fcdd5f806e7901e83a))
+* **cli:**  Added 'cls' command to 'watch' mode (#474) ([4f2468e1](https://github.com/rust-lang/rustlings/commit/4f2468e14f574a93a2e9b688367b5752ed96ae7b))
+* **try_from_into:**  Add insufficient length test (#469) ([523d18b8](https://github.com/rust-lang/rustlings/commit/523d18b873a319f7c09262f44bd40e2fab1830e5))
+
+<a name="4.0.0"></a>
+## 4.0.0 (2020-07-08)
+
+#### Breaking Changes
+
+*   Add a --nocapture option to display test harnesses' outputs ([8ad5f9bf](https://github.com/rust-lang/rustlings/commit/8ad5f9bf531a4848b1104b7b389a20171624c82f))
+*   Rename test to quiz, fixes #244 ([010a0456](https://github.com/rust-lang/rustlings/commit/010a04569282149cea7f7a76fc4d7f4c9f0f08dd))
+
+#### Features
+
+*   Add traits README ([173bb141](https://github.com/rust-lang/rustlings/commit/173bb14140c5530cbdb59e53ace3991a99d804af))
+*   Add box1.rs exercise ([7479a473](https://github.com/rust-lang/rustlings/commit/7479a4737bdcac347322ad0883ca528c8675e720))
+*   Rewrite try_from_into (#393) ([763aa6e3](https://github.com/rust-lang/rustlings/commit/763aa6e378a586caae2d8d63755a85eeba227933))
+*   Add if2 exercise ([1da84b5f](https://github.com/rust-lang/rustlings/commit/1da84b5f7c489f65bd683c244f13c7d1ee812df0))
+*   Added exercise structs3.rs ([b66e2e09](https://github.com/rust-lang/rustlings/commit/b66e2e09622243e086a0f1258dd27e1a2d61c891))
+*   Add exercise variables6 covering const (#352) ([5999acd2](https://github.com/rust-lang/rustlings/commit/5999acd24a4f203292be36e0fd18d385887ec481))
+
+#### Bug Fixes
+
+*   Change then to than ([ddd98ad7](https://github.com/rust-lang/rustlings/commit/ddd98ad75d3668fbb10eff74374148aa5ed2344d))
+*   rename quiz1 to tests1 in info (#420) ([0dd1c6ca](https://github.com/rust-lang/rustlings/commit/0dd1c6ca6b389789e0972aa955fe17aa15c95f29))
+*   fix quiz naming inconsistency (#421) ([5563adbb](https://github.com/rust-lang/rustlings/commit/5563adbb890587fc48fbbc9c4028642687f1e85b))
+*   confine the user further in variable exercises ([06ef4cc6](https://github.com/rust-lang/rustlings/commit/06ef4cc654e75d22a526812919ee49b8956280bf))
+*   update iterator and macro text for typos and clarity ([95900828](https://github.com/rust-lang/rustlings/commit/959008284834bece0196a01e17ac69a7e3590116))
+*   update generics2       closes #362 ([964c974a](https://github.com/rust-lang/rustlings/commit/964c974a0274199d755073b917c2bc5da0c9b4f1))
+*   confusing comment in conversions/try_from_into.rs ([c9e4f2cf](https://github.com/rust-lang/rustlings/commit/c9e4f2cfb4c48d0b7451263cfb43b9426438122d))
+* **arc1:**  Passively introduce attributes (#429) ([113cdae2](https://github.com/rust-lang/rustlings/commit/113cdae2d4e4c55905e8056ad326ede7fd7de356))
+* **box1:**  fix comment typo (#426) ([bb2ca251](https://github.com/rust-lang/rustlings/commit/bb2ca251106b27a7272d9a30872904dd1376654c))
+* **errorsn:**  Try harder to confine the user. (#388) ([2b20c8a0](https://github.com/rust-lang/rustlings/commit/2b20c8a0f5774d07c58d110d75879f33fc6273b5))
+* **from_into.rs:**  typo ([a901499e](https://github.com/rust-lang/rustlings/commit/a901499ededd3ce1995164700514fe4e9a0373ea))
+* **generics2:**  Guide students to the answer (#430) ([e6bd8021](https://github.com/rust-lang/rustlings/commit/e6bd8021d9a7dd06feebc30c9d5f953901d7b419))
+* **installation:**
+  *  Provide a backup git reference when tag can't be curl ([9e4fb100](https://github.com/rust-lang/rustlings/commit/9e4fb1009f1c9e3433915c03e22c2af422e5c5fe))
+  *  Check if python is available while checking for git,rustc and cargo ([9cfb617d](https://github.com/rust-lang/rustlings/commit/9cfb617d5b0451b4b51644a1298965390cda9884))
+* **option1:**
+  *  Don't add only zeros to the numbers array ([cce6a442](https://github.com/rust-lang/rustlings/commit/cce6a4427718724a9096800754cd3abeca6a1580))
+  *  Add cast to usize, as it is confusing in the context of an exercise about Option ([f6cffc7e](https://github.com/rust-lang/rustlings/commit/f6cffc7e487b42f15a6f958e49704c93a8d4465b))
+* **option2:**  Add TODO to comments (#400) ([10967bce](https://github.com/rust-lang/rustlings/commit/10967bce57682812dc0891a9f9757da1a9d87404))
+* **options1:**  Add hint about Array Initialization (#389) ([9f75554f](https://github.com/rust-lang/rustlings/commit/9f75554f2a30295996f03f0160b98c0458305502))
+* **test2:**  name of type String and &str (#394) ([d6c0a688](https://github.com/rust-lang/rustlings/commit/d6c0a688e6a96f93ad60d540d4b326f342fc0d45))
+* **variables6:**  minor typo (#419) ([524e17df](https://github.com/rust-lang/rustlings/commit/524e17df10db95f7b90a0f75cc8997182a8a4094))
+
+<a name="3.0.0"></a>
+## 3.0.0 (2020-04-11)
+
+#### Breaking Changes
+
+* make "compile" exercises print output (#278) ([3b6d5c](https://github.com/fmoko/rustlings/commit/3b6d5c3aaa27a242a832799eb66e96897d26fde3))
+
+#### Bug Fixes
+
+* **primitive_types:** revert primitive_types4 (#296) ([b3a3351e](https://github.com/rust-lang/rustlings/commit/b3a3351e8e6a0bdee07077d7b0382953821649ae))
+* **run:**  compile clippy exercise files (#295) ([3ab084a4](https://github.com/rust-lang/rustlings/commit/3ab084a421c0f140ae83bf1fc3f47b39342e7373))
+* **conversions:**
+  * add additional test to meet exercise rules (#284) ([bc22ec3](https://github.com/fmoko/rustlings/commit/bc22ec382f843347333ef1301fc1bad773657f38))
+  * remove duplicate not done comment (#292) ([dab90f](https://github.com/fmoko/rustlings/commit/dab90f7b91a6000fe874e3d664f244048e5fa342))
+* don't hardcode documentation version for traits (#288) ([30e6af](https://github.com/fmoko/rustlings/commit/30e6af60690c326fb5d3a9b7335f35c69c09137d))
+
+#### Features
+
+*   add Option2 exercise (#290) ([86b5c08b](https://github.com/rust-lang/rustlings/commit/86b5c08b9bea1576127a7c5f599f5752072c087d))
+*   add excercise for option (#282) ([135e5d47](https://github.com/rust-lang/rustlings/commit/135e5d47a7c395aece6f6022117fb20c82f2d3d4))
+*   add new exercises for generics (#280) ([76be5e4e](https://github.com/rust-lang/rustlings/commit/76be5e4e991160f5fd9093f03ee2ba260e8f7229))
+* **ci:**  add buildkite config ([b049fa2c](https://github.com/rust-lang/rustlings/commit/b049fa2c84dba0f0c8906ac44e28fd45fba51a71))
+
+<a name="2.2.1"></a>
+### 2.2.1 (2020-02-27)
+
+#### Bug Fixes
+
+*   Re-add cloning the repo to install scripts ([3d9b03c5](https://github.com/rust-lang/rustlings/commit/3d9b03c52b8dc51b140757f6fd25ad87b5782ef5))
+
+#### Features
+
+*   Add clippy lints (#269) ([1e2fd9c9](https://github.com/rust-lang/rustlings/commit/1e2fd9c92f8cd6e389525ca1a999fca4c90b5921))
+
+<a name="2.2.0"></a>
+## 2.2.0 (2020-02-25)
+
+
+#### Bug Fixes
+
+*   Update deps to version compatable with aarch64-pc-windows (#263) ([19a93428](https://github.com/rust-lang/rustlings/commit/19a93428b3c73d994292671f829bdc8e5b7b3401))
+* **docs:**
+  * Added a necessary step to Windows installation process (#242) ([3906efcd](https://github.com/rust-lang/rustlings/commit/3906efcd52a004047b460ed548037093de3f523f))
+  * Fixed mangled sentence from book; edited for clarity (#266) ([ade52ff](https://github.com/rust-lang/rustlings/commit/ade52ffb739987287ddd5705944c8777705faed9))
+  * Updated iterators readme to account for iterators4 exercise (#273) ([bec8e3a](https://github.com/rust-lang/rustlings/commit/bec8e3a644cbd88db1c73ea5f1d8a364f4a34016))
+* **installation:**  make fatal errors more obvious (#272) ([17d0951e](https://github.com/rust-lang/rustlings/commit/17d0951e66fda8e11b204d5c4c41a0d5e22e78f7))
+* **iterators2:**
+  *  Remove reference to missing iterators2.rs (#245) ([419f7797](https://github.com/rust-lang/rustlings/commit/419f7797f294e4ce6a2b883199731b5bde77d262))
+* **as_ref_mut:** Enable a test and improve per clippy's suggestion (#256) ([dfdf809](https://github.com/rust-lang/rustlings/commit/dfdf8093ebbd4145864995627b812780de52f902))
+* **tests1:**
+  * Change test command ([fe10e06c](https://github.com/rust-lang/rustlings/commit/fe10e06c3733ddb4a21e90d09bf79bfe618e97ce)
+  * Correct test command in tests1.rs comment (#263) ([39fa7ae](https://github.com/rust-lang/rustlings/commit/39fa7ae8b70ad468da49b06f11b2383135a63bcf))
+
+#### Features
+
+*   Add variables5.rs exercise (#264) ([0c73609e](https://github.com/rust-lang/rustlings/commit/0c73609e6f2311295e95d6f96f8c747cfc4cba03))
+*   Show a completion message when watching (#253) ([d25ee55a](https://github.com/rust-lang/rustlings/commit/d25ee55a3205882d35782e370af855051b39c58c))
+*   Add type conversion and parsing exercises (#249) ([0c85dc11](https://github.com/rust-lang/rustlings/commit/0c85dc1193978b5165491b99cc4922caf8d14a65))
+*   Created consistent money unit (#258) ([fd57f8f](https://github.com/rust-lang/rustlings/commit/fd57f8f2c1da2af8ddbebbccec214e6f40f4dbab))
+*   Enable test for exercise test4 (#276) ([8b971ff](https://github.com/rust-lang/rustlings/commit/8b971ffab6079a706ac925f5917f987932b55c07))
+*   Added traits exercises (#274 but specifically #216, which originally added
+    this :heart:) ([b559cdd](https://github.com/rust-lang/rustlings/commit/b559cdd73f32c0d0cfc1feda39f82b3e3583df17))
+
+
+<a name="2.1.0"></a>
+## 2.1.0 (2019-11-27)
+
+#### Bug Fixes
+
+* add line numbers in several exercises and hints ([b565c4d3](https://github.com/rust-lang/rustlings/commit/b565c4d3e74e8e110bef201a082fa1302722a7c3))
+* **arc1:**  Fix some words in the comment ([c42c3b21](https://github.com/rust-lang/rustlings/commit/c42c3b2101df9164c8cd7bb344def921e5ba3e61))
+* **enums:**  Add link to chapter on pattern syntax (#242) ([615ce327](https://github.com/rust-lang/rustlings/commit/615ce3279800c56d89f19d218ccb7ef576624feb))
+* **primitive_types4:**
+  *  update outdated hint ([4c5189df](https://github.com/rust-lang/rustlings/commit/4c5189df2bdd9a231f6b2611919ba5aa14da0d3f))
+  *  update outdated comment ([ded2c034](https://github.com/rust-lang/rustlings/commit/ded2c034ba93fa1e3c2c2ea16b83abc1a57265e8))
+* **strings2:**  update line number in hint ([a09f684f](https://github.com/rust-lang/rustlings/commit/a09f684f05c58d239a6fc59ec5f81c2533e8b820))
+* **variables1:**  Correct wrong word in comment ([fda5a470](https://github.com/rust-lang/rustlings/commit/fda5a47069e0954f16a04e8e50945e03becb71a5))
+
+#### Features
+
+* **watch:**  show hint while watching ([8143d57b](https://github.com/rust-lang/rustlings/commit/8143d57b4e88c51341dd4a18a14c536042cc009c))
+
 <a name="2.0.0"></a>
 ## 2.0.0 (2019-11-12)
 

CONTRIBUTING.md

@@ -26,12 +26,12 @@ isn't really that complicated since the bulk of the work is done by `rustc`.
 <a name="addex"></a>
 ### Adding an exercise
 
-First step is to add the exercise! Call it `exercises/yourTopic/yourTopicN.rs`, make sure to
+The first step is to add the exercise! Name the file `exercises/yourTopic/yourTopicN.rs`, make sure to
 put in some helpful links, and link to sections of the book in `exercises/yourTopic/README.md`.
 
-Next you want to make sure it runs when using `rustlings`. All exercises are stored in `info.toml`, under the `exercises` array. They're ordered by the order they're ran when using `rustlings verify`.
+Next make sure it runs with `rustlings`. The exercise metadata is stored in `info.toml`, under the `exercises` array. The order of the `exercises` array determines the order the exercises are run by `rustlings verify`.
 
-You want to make sure where in the file you add your exercise. If you're not sure, add it at the bottom and ask in your pull request. To add an exercise, edit the file like this:
+Add the metadata for your exercise in the correct order in the `exercises` array. If you are unsure of the correct ordering, add it at the bottom and ask in your pull request. The exercise metadata should contain the following:
 ```diff
   ...
 + [[exercises]]

Cargo.toml

@@ -1,17 +1,17 @@
 [package]
 name = "rustlings"
-version = "2.0.0"
-authors = ["Marisa <mokou@posteo.de>", "Carol (Nichols || Goulding) <carol.nichols@gmail.com"]
-edition = "2018"
+version = "4.7.0"
+authors = ["mokou <mokou@fastmail.com>", "Carol (Nichols || Goulding) <carol.nichols@gmail.com>"]
+edition = "2021"
 
 [dependencies]
-clap = "2.32.0"
-indicatif = "0.9.0"
-console = "0.6.2"
-notify = "4.0.0"
+argh = "0.1.4"
+indicatif = "0.10.3"
+console = "0.7.7"
+notify = "4.0.15"
 toml = "0.4.10"
 regex = "1.1.6"
-serde = {version = "1.0.10", features = ["derive"]}
+serde = { version = "1.0.10", features = ["derive"] }
 
 [[bin]]
 name = "rustlings"
@@ -21,3 +21,6 @@ path = "src/main.rs"
 assert_cmd = "0.11.0"
 predicates = "1.0.1"
 glob = "0.3.0"
+
+[features]
+exercises = []

README.md

@@ -1,12 +1,10 @@
-![crab pet](https://i.imgur.com/LbZJgmm.gif)
-
 # rustlings 🦀❤️
 
 Greetings and welcome to `rustlings`. This project contains small exercises to get you used to reading and writing Rust code. This includes reading and responding to compiler messages!
 
 _...looking for the old, web-based version of Rustlings? Try [here](https://github.com/rust-lang/rustlings/tree/rustlings-1)_
 
-Alternatively, for a first-time Rust learner, there's several other resources:
+Alternatively, for a first-time Rust learner, there are several other resources:
 
 - [The Book](https://doc.rust-lang.org/book/index.html) - The most comprehensive resource for learning Rust, but a bit theoretical sometimes. You will be using this along with Rustlings!
 - [Rust By Example](https://doc.rust-lang.org/rust-by-example/index.html) - Learn Rust by solving little exercises! It's almost like `rustlings`, but online
@@ -14,8 +12,7 @@ Alternatively, for a first-time Rust learner, there's several other resources:
 ## Getting Started
 
 _Note: If you're on MacOS, make sure you've installed Xcode and its developer tools by typing `xcode-select --install`._
-
-_Note: If you have Xcode 10+ installed, you also need to install the package file found at `/Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg`._
+_Note: If you're on Linux, make sure you've installed gcc. Deb: `sudo apt install gcc`. Yum: `sudo yum -y install gcc`._
 
 You will need to have Rust installed. You can get it by visiting https://rustup.rs. This'll also install Cargo, Rust's package/project manager.
 
@@ -24,35 +21,50 @@ You will need to have Rust installed. You can get it by visiting https://rustup.
 Just run:
 
 ```bash
-curl -L https://git.io/rustlings | bash
+curl -L https://git.io/install-rustlings | bash
 # Or if you want it to be installed to a different path:
-curl -L https://git.io/rustlings | bash -s mypath/
+curl -L https://git.io/install-rustlings | bash -s mypath/
 ```
 
 This will install Rustlings and give you access to the `rustlings` command. Run it to get started!
 
 ## Windows
 
-You can run:
+In PowerShell (Run as Administrator), set `ExecutionPolicy` to `RemoteSigned`:
 
-```ps
-Invoke-WebRequest https://git.io/rustlings-win | Select-Object -ExpandProperty Content | Out-File $env:TMP/install_rustlings.ps1; Unblock-File $env:TMP/install_rustlings.ps1; Invoke-Expression $env:TMP/install_rustlings.ps1
+```ps1
+Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser
+```
+
+Then, you can run:
+
+```ps1
+Start-BitsTransfer -Source https://git.io/JTL5v -Destination $env:TMP/install_rustlings.ps1; Unblock-File $env:TMP/install_rustlings.ps1; Invoke-Expression $env:TMP/install_rustlings.ps1
 ```
 
 To install Rustlings. Same as on MacOS/Linux, you will have access to the `rustlings` command after it.
 
+When you get a permission denied message then you have to exclude the directory where you placed the rustlings in your virus-scanner
+
+## Browser:
+
+[Run on Repl.it](https://repl.it/github/rust-lang/rustlings)
+
+[Open in Gitpod](https://gitpod.io/#https://github.com/rust-lang/rustlings)
+
 ## Manually
 
-Basically: Clone the repository, checkout to the latest tag, run `cargo install`.
+Basically: Clone the repository at the latest tag, run `cargo install`.
 
 ```bash
-git clone https://github.com/rust-lang/rustlings
+# find out the latest version at https://github.com/rust-lang/rustlings/releases/latest (on edit 4.6.0)
+git clone -b 4.6.0 --depth 1 https://github.com/rust-lang/rustlings
 cd rustlings
-git checkout tags/2.0.0 # or whatever the latest version is (find out at https://github.com/rust-lang/rustlings/releases/latest)
 cargo install --force --path .
 ```
 
 If there are installation errors, ensure that your toolchain is up to date. For the latest, run:
+
 ```bash
 rustup update
 ```
@@ -63,7 +75,7 @@ Then, same as above, run `rustlings` to get started.
 
 The exercises are sorted by topic and can be found in the subdirectory `rustlings/exercises/<topic>`. For every topic there is an additional README file with some resources to get you started on the topic. We really recommend that you have a look at them before you start.
 
-The task is simple. Most exercises contain an error that keep it from compiling, and it's up to you to fix it! Some exercises are also run as tests, but rustlings handles them all the same. To run the exercises in the recommended order, execute:
+The task is simple. Most exercises contain an error that keeps them from compiling, and it's up to you to fix it! Some exercises are also run as tests, but rustlings handles them all the same. To run the exercises in the recommended order, execute:
 
 ```bash
 rustlings watch
@@ -83,16 +95,77 @@ In case you want to go by your own order, or want to only verify a single exerci
 rustlings run myExercise1
 ```
 
+Or simply use the following command to run the next unsolved exercise in the course:
+
+```bash
+rustlings run next
+```
+
 In case you get stuck, you can run the following command to get a hint for your
 exercise:
 
-``` bash
+```bash
 rustlings hint myExercise1
 ```
 
+You can also get the hint for the next unsolved exercise with the following command:
+
+```bash
+rustlings hint next
+```
+
+To check your progress, you can run the following command:
+
+```bash
+rustlings list
+```
+
 ## Testing yourself
 
-After every couple of sections, there will be a test that'll test your knowledge on a bunch of sections at once. These tests are found in `exercises/testN.rs`.
+After every couple of sections, there will be a quiz that'll test your knowledge on a bunch of sections at once. These quizzes are found in `exercises/quizN.rs`.
+
+## Enabling `rust-analyzer`
+
+`rust-analyzer` support is provided, but it depends on your editor
+whether it's enabled by default. (RLS support is not provided)
+
+To enable `rust-analyzer`, you'll need to make Cargo build the project
+with the `exercises` feature, which will automatically include the `exercises/`
+subfolder in the project. The easiest way to do this is to tell your editor to
+build the project with all features (the equivalent of `cargo build --all-features`).
+For specific editor instructions:
+
+- **VSCode**: Add a `.vscode/settings.json` file with the following:
+```json
+{
+    "rust-analyzer.cargo.features": ["exercises"]
+}
+```
+- **IntelliJ-based Editors**: Using the Rust plugin, everything should work
+    by default.
+- _Missing your editor? Feel free to contribute more instructions!_
+
+## Continuing On
+
+Once you've completed Rustlings, put your new knowledge to good use! Continue practicing your Rust skills by building your own projects, contributing to Rustlings, or finding other open-source projects to contribute to.
+
+## Uninstalling Rustlings
+
+If you want to remove Rustlings from your system, there's two steps. First, you'll need to remove the exercises folder that the install script created
+for you:
+
+```bash
+rm -rf rustlings # or your custom folder name, if you chose and or renamed it
+```
+
+Second, since Rustlings got installed via `cargo install`, it's only reasonable to assume that you can also remove it using Cargo, and
+exactly that is the case. Run `cargo uninstall` to remove the `rustlings` binary:
+
+```bash
+cargo uninstall rustlings
+```
+
+Now you should be done!
 
 ## Completion
 
@@ -116,7 +189,6 @@ If you are interested in improving or adding new ones, please feel free to contr
 
 See [CONTRIBUTING.md](./CONTRIBUTING.md).
 
-## Credits
-
-`rustlings` was originally written by [Carol](https://github.com/carols10cents)!
+## Contributors ✨
 
+Thanks goes to the wonderful people listed in [AUTHORS.md](./AUTHORS.md) 🎉

default_out.txt

@@ -1,19 +0,0 @@
-Thanks for installing Rustlings!
-
-Is this your first time?
-
-Let's make sure you're up to speed:
-- You have Rust installed, preferably via `rustup`
-- You have `~/.cargo/bin` added to your PATH variable
-- You have cloned this repository (https://github.com/rust-lang/rustlings)
-- You have installed Rust language support for your editor
-- You have locally installed the `rustlings` command by running an
-  installation script or manually executing:
-
-cargo install --force --path .
-
-If you've done all of this (or even most of it), congrats! You're ready
-to start working with Rust.
-
-To get started, run `rustlings watch` in order to get the first exercise.
-Make sure to have your editor open!

exercises/README.md

@@ -0,0 +1,24 @@
+# Exercise to Book Chapter mapping
+
+| Exercise               | Book Chapter |
+|------------------------|--------------|
+| variables              | §3.1          |
+| functions              | §3.3          |
+| if                     | §3.5          |
+| move_semantics         | §4.1          |
+| primitive_types        | §4.3          |
+| structs                | §5.1          |
+| enums                  | §6            |
+| modules                | §7            |
+| collections            | §8.1, §8.3    |
+| strings                | §8.2          |
+| error_handling         | §9            |
+| generics               | §10           |
+| option                 | §10.1         |
+| traits                 | §10.2         |
+| tests                  | §11.1         |
+| standard_library_types | §13.2         |
+| threads                | §16.1         |
+| macros                 | §19.6         |
+| clippy                 | n/a           |
+| conversions            | n/a           |

exercises/advanced_errors/advanced_errs1.rs

@@ -0,0 +1,98 @@
+// advanced_errs1.rs
+
+// Remember back in errors6, we had multiple mapping functions so that we
+// could translate lower-level errors into our custom error type using
+// `map_err()`? What if we could use the `?` operator directly instead?
+
+// Make this code compile! Execute `rustlings hint advanced_errs1` for
+// hints :)
+
+// I AM NOT DONE
+
+use std::num::ParseIntError;
+use std::str::FromStr;
+
+// This is a custom error type that we will be using in the `FromStr`
+// implementation.
+#[derive(PartialEq, Debug)]
+enum ParsePosNonzeroError {
+    Creation(CreationError),
+    ParseInt(ParseIntError),
+}
+
+impl From<CreationError> for ParsePosNonzeroError {
+    fn from(e: CreationError) -> Self {
+        // TODO: complete this implementation so that the `?` operator will
+        // work for `CreationError`
+    }
+}
+
+// TODO: implement another instance of the `From` trait here so that the
+// `?` operator will work in the other place in the `FromStr`
+// implementation below.
+
+// Don't change anything below this line.
+
+impl FromStr for PositiveNonzeroInteger {
+    type Err = ParsePosNonzeroError;
+    fn from_str(s: &str) -> Result<PositiveNonzeroInteger, Self::Err> {
+        let x: i64 = s.parse()?;
+        Ok(PositiveNonzeroInteger::new(x)?)
+    }
+}
+
+#[derive(PartialEq, Debug)]
+struct PositiveNonzeroInteger(u64);
+
+#[derive(PartialEq, Debug)]
+enum CreationError {
+    Negative,
+    Zero,
+}
+
+impl PositiveNonzeroInteger {
+    fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
+        match value {
+            x if x < 0 => Err(CreationError::Negative),
+            x if x == 0 => Err(CreationError::Zero),
+            x => Ok(PositiveNonzeroInteger(x as u64)),
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_parse_error() {
+        // We can't construct a ParseIntError, so we have to pattern match.
+        assert!(matches!(
+            PositiveNonzeroInteger::from_str("not a number"),
+            Err(ParsePosNonzeroError::ParseInt(_))
+        ));
+    }
+
+    #[test]
+    fn test_negative() {
+        assert_eq!(
+            PositiveNonzeroInteger::from_str("-555"),
+            Err(ParsePosNonzeroError::Creation(CreationError::Negative))
+        );
+    }
+
+    #[test]
+    fn test_zero() {
+        assert_eq!(
+            PositiveNonzeroInteger::from_str("0"),
+            Err(ParsePosNonzeroError::Creation(CreationError::Zero))
+        );
+    }
+
+    #[test]
+    fn test_positive() {
+        let x = PositiveNonzeroInteger::new(42);
+        assert!(x.is_ok());
+        assert_eq!(PositiveNonzeroInteger::from_str("42"), Ok(x.unwrap()));
+    }
+}

exercises/advanced_errors/advanced_errs2.rs

@@ -0,0 +1,202 @@
+// advanced_errs2.rs
+
+// This exercise demonstrates a few traits that are useful for custom error
+// types to implement, especially so that other code can consume the custom
+// error type more usefully.
+
+// Make this compile, and make the tests pass!
+// Execute `rustlings hint advanced_errs2` for hints.
+
+// Steps:
+// 1. Implement a missing trait so that `main()` will compile.
+// 2. Complete the partial implementation of `From` for
+//    `ParseClimateError`.
+// 3. Handle the missing error cases in the `FromStr` implementation for
+//    `Climate`.
+// 4. Complete the partial implementation of `Display` for
+//    `ParseClimateError`.
+
+// I AM NOT DONE
+
+use std::error::Error;
+use std::fmt::{self, Display, Formatter};
+use std::num::{ParseFloatError, ParseIntError};
+use std::str::FromStr;
+
+// This is the custom error type that we will be using for the parser for
+// `Climate`.
+#[derive(Debug, PartialEq)]
+enum ParseClimateError {
+    Empty,
+    BadLen,
+    NoCity,
+    ParseInt(ParseIntError),
+    ParseFloat(ParseFloatError),
+}
+
+// This `From` implementation allows the `?` operator to work on
+// `ParseIntError` values.
+impl From<ParseIntError> for ParseClimateError {
+    fn from(e: ParseIntError) -> Self {
+        Self::ParseInt(e)
+    }
+}
+
+// This `From` implementation allows the `?` operator to work on
+// `ParseFloatError` values.
+impl From<ParseFloatError> for ParseClimateError {
+    fn from(e: ParseFloatError) -> Self {
+        // TODO: Complete this function
+    }
+}
+
+// TODO: Implement a missing trait so that `main()` below will compile. It
+// is not necessary to implement any methods inside the missing trait.
+
+// The `Display` trait allows for other code to obtain the error formatted
+// as a user-visible string.
+impl Display for ParseClimateError {
+    // TODO: Complete this function so that it produces the correct strings
+    // for each error variant.
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        // Imports the variants to make the following code more compact.
+        use ParseClimateError::*;
+        match self {
+            NoCity => write!(f, "no city name"),
+            ParseFloat(e) => write!(f, "error parsing temperature: {}", e),
+        }
+    }
+}
+
+#[derive(Debug, PartialEq)]
+struct Climate {
+    city: String,
+    year: u32,
+    temp: f32,
+}
+
+// Parser for `Climate`.
+// 1. Split the input string into 3 fields: city, year, temp.
+// 2. Return an error if the string is empty or has the wrong number of
+//    fields.
+// 3. Return an error if the city name is empty.
+// 4. Parse the year as a `u32` and return an error if that fails.
+// 5. Parse the temp as a `f32` and return an error if that fails.
+// 6. Return an `Ok` value containing the completed `Climate` value.
+impl FromStr for Climate {
+    type Err = ParseClimateError;
+    // TODO: Complete this function by making it handle the missing error
+    // cases.
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let v: Vec<_> = s.split(',').collect();
+        let (city, year, temp) = match &v[..] {
+            [city, year, temp] => (city.to_string(), year, temp),
+            _ => return Err(ParseClimateError::BadLen),
+        };
+        let year: u32 = year.parse()?;
+        let temp: f32 = temp.parse()?;
+        Ok(Climate { city, year, temp })
+    }
+}
+
+// Don't change anything below this line (other than to enable ignored
+// tests).
+
+fn main() -> Result<(), Box<dyn Error>> {
+    println!("{:?}", "Hong Kong,1999,25.7".parse::<Climate>()?);
+    println!("{:?}", "".parse::<Climate>()?);
+    Ok(())
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    #[test]
+    fn test_empty() {
+        let res = "".parse::<Climate>();
+        assert_eq!(res, Err(ParseClimateError::Empty));
+        assert_eq!(res.unwrap_err().to_string(), "empty input");
+    }
+    #[test]
+    fn test_short() {
+        let res = "Boston,1991".parse::<Climate>();
+        assert_eq!(res, Err(ParseClimateError::BadLen));
+        assert_eq!(res.unwrap_err().to_string(), "incorrect number of fields");
+    }
+    #[test]
+    fn test_long() {
+        let res = "Paris,1920,17.2,extra".parse::<Climate>();
+        assert_eq!(res, Err(ParseClimateError::BadLen));
+        assert_eq!(res.unwrap_err().to_string(), "incorrect number of fields");
+    }
+    #[test]
+    fn test_no_city() {
+        let res = ",1997,20.5".parse::<Climate>();
+        assert_eq!(res, Err(ParseClimateError::NoCity));
+        assert_eq!(res.unwrap_err().to_string(), "no city name");
+    }
+    #[test]
+    fn test_parse_int_neg() {
+        let res = "Barcelona,-25,22.3".parse::<Climate>();
+        assert!(matches!(res, Err(ParseClimateError::ParseInt(_))));
+        let err = res.unwrap_err();
+        if let ParseClimateError::ParseInt(ref inner) = err {
+            assert_eq!(
+                err.to_string(),
+                format!("error parsing year: {}", inner.to_string())
+            );
+        } else {
+            unreachable!();
+        };
+    }
+    #[test]
+    fn test_parse_int_bad() {
+        let res = "Beijing,foo,15.0".parse::<Climate>();
+        assert!(matches!(res, Err(ParseClimateError::ParseInt(_))));
+        let err = res.unwrap_err();
+        if let ParseClimateError::ParseInt(ref inner) = err {
+            assert_eq!(
+                err.to_string(),
+                format!("error parsing year: {}", inner.to_string())
+            );
+        } else {
+            unreachable!();
+        };
+    }
+    #[test]
+    fn test_parse_float() {
+        let res = "Manila,2001,bar".parse::<Climate>();
+        assert!(matches!(res, Err(ParseClimateError::ParseFloat(_))));
+        let err = res.unwrap_err();
+        if let ParseClimateError::ParseFloat(ref inner) = err {
+            assert_eq!(
+                err.to_string(),
+                format!("error parsing temperature: {}", inner.to_string())
+            );
+        } else {
+            unreachable!();
+        };
+    }
+    #[test]
+    fn test_parse_good() {
+        let res = "Munich,2015,23.1".parse::<Climate>();
+        assert_eq!(
+            res,
+            Ok(Climate {
+                city: "Munich".to_string(),
+                year: 2015,
+                temp: 23.1,
+            })
+        );
+    }
+    #[test]
+    #[ignore]
+    fn test_downcast() {
+        let res = "São Paulo,-21,28.5".parse::<Climate>();
+        assert!(matches!(res, Err(ParseClimateError::ParseInt(_))));
+        let err = res.unwrap_err();
+        let inner: Option<&(dyn Error + 'static)> = err.source();
+        assert!(inner.is_some());
+        assert!(inner.unwrap().is::<ParseIntError>());
+    }
+}

exercises/advanced_errors/mod.rs

@@ -0,0 +1,2 @@
+mod advanced_errs1;
+mod advanced_errs2;

exercises/clippy/README.md

@@ -0,0 +1,10 @@
+# Clippy
+
+The Clippy tool is a collection of lints to analyze your code so you can catch common mistakes and improve your Rust code.
+
+If you used the installation script for Rustlings, Clippy should be already installed.
+If not you can install it manually via `rustup component add clippy`.
+
+## Further information
+
+- [GitHub Repository](https://github.com/rust-lang/rust-clippy).

exercises/clippy/clippy1.rs

@@ -0,0 +1,23 @@
+// clippy1.rs
+// The Clippy tool is a collection of lints to analyze your code
+// so you can catch common mistakes and improve your Rust code.
+//
+// For these exercises the code will fail to compile when there are clippy warnings
+// check clippy's suggestions from the output to solve the exercise.
+// Execute `rustlings hint clippy1` for hints :)
+
+// I AM NOT DONE
+
+use std::f32;
+
+fn main() {
+    let pi = 3.14f32;
+    let radius = 5.00f32;
+
+    let area = pi * f32::powi(radius, 2);
+
+    println!(
+        "The area of a circle with radius {:.2} is {:.5}!",
+        radius, area
+    )
+}

exercises/clippy/clippy2.rs

@@ -0,0 +1,13 @@
+// clippy2.rs
+// Make me compile! Execute `rustlings hint clippy2` for hints :)
+
+// I AM NOT DONE
+
+fn main() {
+    let mut res = 42;
+    let option = Some(12);
+    for x in option {
+        res += x;
+    }
+    println!("{}", res);
+}

exercises/clippy/mod.rs

@@ -0,0 +1,2 @@
+mod clippy1;
+mod clippy2;

exercises/collections/README.md

@@ -0,0 +1,23 @@
+# Collections
+
+Rust’s standard library includes a number of very useful data
+structures called collections. Most other data types represent one
+specific value, but collections can contain multiple values. Unlike
+the built-in array and tuple types, the data these collections point
+to is stored on the heap, which means the amount of data does not need
+to be known at compile time and can grow or shrink as the program
+runs.
+
+This exercise will get you familiar with two fundamental data
+structures that are used very often in Rust programs:
+
+* A *vector* allows you to store a variable number of values next to
+  each other.
+* A *hash map* allows you to associate a value with a particular key.
+  You may also know this by the names [*unordered map* in C++](https://en.cppreference.com/w/cpp/container/unordered_map), 
+  [*dictionary* in Python](https://docs.python.org/3/tutorial/datastructures.html#dictionaries) or an *associative array* in other languages.
+
+## Further information
+
+- [Storing Lists of Values with Vectors](https://doc.rust-lang.org/stable/book/ch08-01-vectors.html)
+- [Storing Keys with Associated Values in Hash Maps](https://doc.rust-lang.org/book/ch08-03-hash-maps.html)

exercises/collections/hashmap1.rs

@@ -0,0 +1,44 @@
+// hashmap1.rs
+// A basket of fruits in the form of a hash map needs to be defined.
+// The key represents the name of the fruit and the value represents
+// how many of that particular fruit is in the basket. You have to put
+// at least three different types of fruits (e.g apple, banana, mango)
+// in the basket and the total count of all the fruits should be at
+// least five.
+//
+// Make me compile and pass the tests!
+//
+// Execute the command `rustlings hint hashmap1` if you need
+// hints.
+
+// I AM NOT DONE
+
+use std::collections::HashMap;
+
+fn fruit_basket() -> HashMap<String, u32> {
+    let mut basket = // TODO: declare your hash map here.
+
+    // Two bananas are already given for you :)
+    basket.insert(String::from("banana"), 2);
+
+    // TODO: Put more fruits in your basket here.
+
+    basket
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn at_least_three_types_of_fruits() {
+        let basket = fruit_basket();
+        assert!(basket.len() >= 3);
+    }
+
+    #[test]
+    fn at_least_five_fruits() {
+        let basket = fruit_basket();
+        assert!(basket.values().sum::<u32>() >= 5);
+    }
+}

exercises/collections/hashmap2.rs

@@ -0,0 +1,81 @@
+// hashmap2.rs
+
+// A basket of fruits in the form of a hash map is given. The key
+// represents the name of the fruit and the value represents how many
+// of that particular fruit is in the basket. You have to put *MORE
+// THAN 11* fruits in the basket. Three types of fruits - Apple (4),
+// Mango (2) and Lychee (5) are already given in the basket. You are
+// not allowed to insert any more of these fruits!
+//
+// Make me pass the tests!
+//
+// Execute the command `rustlings hint hashmap2` if you need
+// hints.
+
+// I AM NOT DONE
+
+use std::collections::HashMap;
+
+#[derive(Hash, PartialEq, Eq)]
+enum Fruit {
+    Apple,
+    Banana,
+    Mango,
+    Lychee,
+    Pineapple,
+}
+
+fn fruit_basket(basket: &mut HashMap<Fruit, u32>) {
+    let fruit_kinds = vec![
+        Fruit::Apple,
+        Fruit::Banana,
+        Fruit::Mango,
+        Fruit::Lychee,
+        Fruit::Pineapple,
+    ];
+
+    for fruit in fruit_kinds {
+        // TODO: Put new fruits if not already present. Note that you
+        // are not allowed to put any type of fruit that's already
+        // present!
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn get_fruit_basket() -> HashMap<Fruit, u32> {
+        let mut basket = HashMap::<Fruit, u32>::new();
+        basket.insert(Fruit::Apple, 4);
+        basket.insert(Fruit::Mango, 2);
+        basket.insert(Fruit::Lychee, 5);
+
+        basket
+    }
+
+    #[test]
+    fn test_given_fruits_are_not_modified() {
+        let mut basket = get_fruit_basket();
+        fruit_basket(&mut basket);
+        assert_eq!(*basket.get(&Fruit::Apple).unwrap(), 4);
+        assert_eq!(*basket.get(&Fruit::Mango).unwrap(), 2);
+        assert_eq!(*basket.get(&Fruit::Lychee).unwrap(), 5);
+    }
+
+    #[test]
+    fn at_least_five_types_of_fruits() {
+        let mut basket = get_fruit_basket();
+        fruit_basket(&mut basket);
+        let count_fruit_kinds = basket.len();
+        assert!(count_fruit_kinds >= 5);
+    }
+
+    #[test]
+    fn greater_than_eleven_fruits() {
+        let mut basket = get_fruit_basket();
+        fruit_basket(&mut basket);
+        let count = basket.values().sum::<u32>();
+        assert!(count > 11);
+    }
+}

exercises/collections/mod.rs

@@ -0,0 +1,4 @@
+mod hashmap1;
+mod hashmap2;
+mod vec1;
+mod vec2;

exercises/collections/vec1.rs

@@ -0,0 +1,25 @@
+// vec1.rs
+// Your task is to create a `Vec` which holds the exact same elements
+// as in the array `a`.
+// Make me compile and pass the test!
+// Execute the command `rustlings hint vec1` if you need hints.
+
+// I AM NOT DONE
+
+fn array_and_vec() -> ([i32; 4], Vec<i32>) {
+    let a = [10, 20, 30, 40]; // a plain array
+    let v = // TODO: declare your vector here with the macro for vectors
+
+    (a, v)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_array_and_vec_similarity() {
+        let (a, v) = array_and_vec();
+        assert_eq!(a, v[..]);
+    }
+}

exercises/collections/vec2.rs

@@ -0,0 +1,33 @@
+// vec2.rs
+// A Vec of even numbers is given. Your task is to complete the loop
+// so that each number in the Vec is multiplied by 2.
+//
+// Make me pass the test!
+//
+// Execute the command `rustlings hint vec2` if you need
+// hints.
+
+// I AM NOT DONE
+
+fn vec_loop(mut v: Vec<i32>) -> Vec<i32> {
+    for i in v.iter_mut() {
+        // TODO: Fill this up so that each element in the Vec `v` is
+        // multiplied by 2.
+    }
+
+    // At this point, `v` should be equal to [4, 8, 12, 16, 20].
+    v
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_vec_loop() {
+        let v: Vec<i32> = (1..).filter(|x| x % 2 == 0).take(5).collect();
+        let ans = vec_loop(v.clone());
+
+        assert_eq!(ans, v.iter().map(|x| x * 2).collect::<Vec<i32>>());
+    }
+}

exercises/conversions/README.md

@@ -0,0 +1,21 @@
+# Type conversions
+
+Rust offers a multitude of ways to convert a value of a given type into another type.
+
+The simplest form of type conversion is a type cast expression. It is denoted with the binary operator `as`. For instance, `println!("{}", 1 + 1.0);` would not compile, since `1` is an integer while `1.0` is a float. However, `println!("{}", 1 as f32 + 1.0)` should compile. The exercise [`using_as`](using_as.rs) tries to cover this.
+
+Rust also offers traits that facilitate type conversions upon implementation. These traits can be found under the [`convert`](https://doc.rust-lang.org/std/convert/index.html) module.
+The traits are the following:
+- `From` and `Into` covered in [`from_into`](from_into.rs)
+- `TryFrom` and `TryInto` covered in [`try_from_into`](try_from_into.rs)
+- `AsRef` and `AsMut` covered in [`as_ref_mut`](as_ref_mut.rs)
+
+Furthermore, the `std::str` module offers a trait called [`FromStr`](https://doc.rust-lang.org/std/str/trait.FromStr.html) which helps with converting strings into target types via the `parse` method on strings. If properly implemented for a given type `Person`, then `let p: Person = "Mark,20".parse().unwrap()` should both compile and run without panicking.
+
+These should be the main ways ***within the standard library*** to convert data into your desired types.
+
+## Further information
+
+These are not directly covered in the book, but the standard library has a great documentation for it.
+- [conversions](https://doc.rust-lang.org/std/convert/index.html)
+- [`FromStr` trait](https://doc.rust-lang.org/std/str/trait.FromStr.html)

exercises/conversions/as_ref_mut.rs

@@ -0,0 +1,52 @@
+// AsRef and AsMut allow for cheap reference-to-reference conversions.
+// Read more about them at https://doc.rust-lang.org/std/convert/trait.AsRef.html
+// and https://doc.rust-lang.org/std/convert/trait.AsMut.html, respectively.
+
+// I AM NOT DONE
+
+// Obtain the number of bytes (not characters) in the given argument
+// Add the AsRef trait appropriately as a trait bound
+fn byte_counter<T>(arg: T) -> usize {
+    arg.as_ref().as_bytes().len()
+}
+
+// Obtain the number of characters (not bytes) in the given argument
+// Add the AsRef trait appropriately as a trait bound
+fn char_counter<T>(arg: T) -> usize {
+    arg.as_ref().chars().count()
+}
+
+fn main() {
+    let s = "Café au lait";
+    println!("{}", char_counter(s));
+    println!("{}", byte_counter(s));
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn different_counts() {
+        let s = "Café au lait";
+        assert_ne!(char_counter(s), byte_counter(s));
+    }
+
+    #[test]
+    fn same_counts() {
+        let s = "Cafe au lait";
+        assert_eq!(char_counter(s), byte_counter(s));
+    }
+
+    #[test]
+    fn different_counts_using_string() {
+        let s = String::from("Café au lait");
+        assert_ne!(char_counter(s.clone()), byte_counter(s));
+    }
+
+    #[test]
+    fn same_counts_using_string() {
+        let s = String::from("Cafe au lait");
+        assert_eq!(char_counter(s.clone()), byte_counter(s));
+    }
+}

exercises/conversions/from_into.rs

@@ -0,0 +1,132 @@
+// The From trait is used for value-to-value conversions.
+// If From is implemented correctly for a type, the Into trait should work conversely.
+// You can read more about it at https://doc.rust-lang.org/std/convert/trait.From.html
+#[derive(Debug)]
+struct Person {
+    name: String,
+    age: usize,
+}
+
+// We implement the Default trait to use it as a fallback
+// when the provided string is not convertible into a Person object
+impl Default for Person {
+    fn default() -> Person {
+        Person {
+            name: String::from("John"),
+            age: 30,
+        }
+    }
+}
+
+// Your task is to complete this implementation
+// in order for the line `let p = Person::from("Mark,20")` to compile
+// Please note that you'll need to parse the age component into a `usize`
+// with something like `"4".parse::<usize>()`. The outcome of this needs to
+// be handled appropriately.
+//
+// Steps:
+// 1. If the length of the provided string is 0, then return the default of Person
+// 2. Split the given string on the commas present in it
+// 3. Extract the first element from the split operation and use it as the name
+// 4. If the name is empty, then return the default of Person
+// 5. Extract the other element from the split operation and parse it into a `usize` as the age
+// If while parsing the age, something goes wrong, then return the default of Person
+// Otherwise, then return an instantiated Person object with the results
+
+// I AM NOT DONE
+
+impl From<&str> for Person {
+    fn from(s: &str) -> Person {
+    }
+}
+
+fn main() {
+    // Use the `from` function
+    let p1 = Person::from("Mark,20");
+    // Since From is implemented for Person, we should be able to use Into
+    let p2: Person = "Gerald,70".into();
+    println!("{:?}", p1);
+    println!("{:?}", p2);
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn test_default() {
+        // Test that the default person is 30 year old John
+        let dp = Person::default();
+        assert_eq!(dp.name, "John");
+        assert_eq!(dp.age, 30);
+    }
+    #[test]
+    fn test_bad_convert() {
+        // Test that John is returned when bad string is provided
+        let p = Person::from("");
+        assert_eq!(p.name, "John");
+        assert_eq!(p.age, 30);
+    }
+    #[test]
+    fn test_good_convert() {
+        // Test that "Mark,20" works
+        let p = Person::from("Mark,20");
+        assert_eq!(p.name, "Mark");
+        assert_eq!(p.age, 20);
+    }
+    #[test]
+    fn test_bad_age() {
+        // Test that "Mark,twenty" will return the default person due to an error in parsing age
+        let p = Person::from("Mark,twenty");
+        assert_eq!(p.name, "John");
+        assert_eq!(p.age, 30);
+    }
+
+    #[test]
+    fn test_missing_comma_and_age() {
+        let p: Person = Person::from("Mark");
+        assert_eq!(p.name, "John");
+        assert_eq!(p.age, 30);
+    }
+
+    #[test]
+    fn test_missing_age() {
+        let p: Person = Person::from("Mark,");
+        assert_eq!(p.name, "John");
+        assert_eq!(p.age, 30);
+    }
+
+    #[test]
+    fn test_missing_name() {
+        let p: Person = Person::from(",1");
+        assert_eq!(p.name, "John");
+        assert_eq!(p.age, 30);
+    }
+
+    #[test]
+    fn test_missing_name_and_age() {
+        let p: Person = Person::from(",");
+        assert_eq!(p.name, "John");
+        assert_eq!(p.age, 30);
+    }
+
+    #[test]
+    fn test_missing_name_and_invalid_age() {
+        let p: Person = Person::from(",one");
+        assert_eq!(p.name, "John");
+        assert_eq!(p.age, 30);
+    }
+
+    #[test]
+    fn test_trailing_comma() {
+        let p: Person = Person::from("Mike,32,");
+        assert_eq!(p.name, "John");
+        assert_eq!(p.age, 30);
+    }
+
+    #[test]
+    fn test_trailing_comma_and_some_string() {
+        let p: Person = Person::from("Mike,32,man");
+        assert_eq!(p.name, "John");
+        assert_eq!(p.age, 30);
+    }
+}

exercises/conversions/from_str.rs

@@ -0,0 +1,122 @@
+// from_str.rs
+// This is similar to from_into.rs, but this time we'll implement `FromStr`
+// and return errors instead of falling back to a default value.
+// Additionally, upon implementing FromStr, you can use the `parse` method
+// on strings to generate an object of the implementor type.
+// You can read more about it at https://doc.rust-lang.org/std/str/trait.FromStr.html
+use std::num::ParseIntError;
+use std::str::FromStr;
+
+#[derive(Debug, PartialEq)]
+struct Person {
+    name: String,
+    age: usize,
+}
+
+// We will use this error type for the `FromStr` implementation.
+#[derive(Debug, PartialEq)]
+enum ParsePersonError {
+    // Empty input string
+    Empty,
+    // Incorrect number of fields
+    BadLen,
+    // Empty name field
+    NoName,
+    // Wrapped error from parse::<usize>()
+    ParseInt(ParseIntError),
+}
+
+// I AM NOT DONE
+
+// Steps:
+// 1. If the length of the provided string is 0, an error should be returned
+// 2. Split the given string on the commas present in it
+// 3. Only 2 elements should be returned from the split, otherwise return an error
+// 4. Extract the first element from the split operation and use it as the name
+// 5. Extract the other element from the split operation and parse it into a `usize` as the age
+//    with something like `"4".parse::<usize>()`
+// 6. If while extracting the name and the age something goes wrong, an error should be returned
+// If everything goes well, then return a Result of a Person object
+
+impl FromStr for Person {
+    type Err = ParsePersonError;
+    fn from_str(s: &str) -> Result<Person, Self::Err> {
+    }
+}
+
+fn main() {
+    let p = "Mark,20".parse::<Person>().unwrap();
+    println!("{:?}", p);
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn empty_input() {
+        assert_eq!("".parse::<Person>(), Err(ParsePersonError::Empty));
+    }
+    #[test]
+    fn good_input() {
+        let p = "John,32".parse::<Person>();
+        assert!(p.is_ok());
+        let p = p.unwrap();
+        assert_eq!(p.name, "John");
+        assert_eq!(p.age, 32);
+    }
+    #[test]
+    fn missing_age() {
+        assert!(matches!(
+            "John,".parse::<Person>(),
+            Err(ParsePersonError::ParseInt(_))
+        ));
+    }
+
+    #[test]
+    fn invalid_age() {
+        assert!(matches!(
+            "John,twenty".parse::<Person>(),
+            Err(ParsePersonError::ParseInt(_))
+        ));
+    }
+
+    #[test]
+    fn missing_comma_and_age() {
+        assert_eq!("John".parse::<Person>(), Err(ParsePersonError::BadLen));
+    }
+
+    #[test]
+    fn missing_name() {
+        assert_eq!(",1".parse::<Person>(), Err(ParsePersonError::NoName));
+    }
+
+    #[test]
+    fn missing_name_and_age() {
+        assert!(matches!(
+            ",".parse::<Person>(),
+            Err(ParsePersonError::NoName | ParsePersonError::ParseInt(_))
+        ));
+    }
+
+    #[test]
+    fn missing_name_and_invalid_age() {
+        assert!(matches!(
+            ",one".parse::<Person>(),
+            Err(ParsePersonError::NoName | ParsePersonError::ParseInt(_))
+        ));
+    }
+
+    #[test]
+    fn trailing_comma() {
+        assert_eq!("John,32,".parse::<Person>(), Err(ParsePersonError::BadLen));
+    }
+
+    #[test]
+    fn trailing_comma_and_some_string() {
+        assert_eq!(
+            "John,32,man".parse::<Person>(),
+            Err(ParsePersonError::BadLen)
+        );
+    }
+}

exercises/conversions/mod.rs

@@ -0,0 +1,5 @@
+mod as_ref_mut;
+mod from_into;
+mod from_str;
+mod try_from_into;
+mod using_as;

exercises/conversions/try_from_into.rs

@@ -0,0 +1,188 @@
+// try_from_into.rs
+// TryFrom is a simple and safe type conversion that may fail in a controlled way under some circumstances.
+// Basically, this is the same as From. The main difference is that this should return a Result type
+// instead of the target type itself.
+// You can read more about it at https://doc.rust-lang.org/std/convert/trait.TryFrom.html
+use std::convert::{TryFrom, TryInto};
+
+#[derive(Debug, PartialEq)]
+struct Color {
+    red: u8,
+    green: u8,
+    blue: u8,
+}
+
+// We will use this error type for these `TryFrom` conversions.
+#[derive(Debug, PartialEq)]
+enum IntoColorError {
+    // Incorrect length of slice
+    BadLen,
+    // Integer conversion error
+    IntConversion,
+}
+
+// I AM NOT DONE
+
+// Your task is to complete this implementation
+// and return an Ok result of inner type Color.
+// You need to create an implementation for a tuple of three integers,
+// an array of three integers, and a slice of integers.
+//
+// Note that the implementation for tuple and array will be checked at compile time,
+// but the slice implementation needs to check the slice length!
+// Also note that correct RGB color values must be integers in the 0..=255 range.
+
+// Tuple implementation
+impl TryFrom<(i16, i16, i16)> for Color {
+    type Error = IntoColorError;
+    fn try_from(tuple: (i16, i16, i16)) -> Result<Self, Self::Error> {
+    }
+}
+
+// Array implementation
+impl TryFrom<[i16; 3]> for Color {
+    type Error = IntoColorError;
+    fn try_from(arr: [i16; 3]) -> Result<Self, Self::Error> {
+    }
+}
+
+// Slice implementation
+impl TryFrom<&[i16]> for Color {
+    type Error = IntoColorError;
+    fn try_from(slice: &[i16]) -> Result<Self, Self::Error> {
+    }
+}
+
+fn main() {
+    // Use the `from` function
+    let c1 = Color::try_from((183, 65, 14));
+    println!("{:?}", c1);
+
+    // Since TryFrom is implemented for Color, we should be able to use TryInto
+    let c2: Result<Color, _> = [183, 65, 14].try_into();
+    println!("{:?}", c2);
+
+    let v = vec![183, 65, 14];
+    // With slice we should use `try_from` function
+    let c3 = Color::try_from(&v[..]);
+    println!("{:?}", c3);
+    // or take slice within round brackets and use TryInto
+    let c4: Result<Color, _> = (&v[..]).try_into();
+    println!("{:?}", c4);
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_tuple_out_of_range_positive() {
+        assert_eq!(
+            Color::try_from((256, 1000, 10000)),
+            Err(IntoColorError::IntConversion)
+        );
+    }
+    #[test]
+    fn test_tuple_out_of_range_negative() {
+        assert_eq!(
+            Color::try_from((-1, -10, -256)),
+            Err(IntoColorError::IntConversion)
+        );
+    }
+    #[test]
+    fn test_tuple_sum() {
+        assert_eq!(
+            Color::try_from((-1, 255, 255)),
+            Err(IntoColorError::IntConversion)
+        );
+    }
+    #[test]
+    fn test_tuple_correct() {
+        let c: Result<Color, _> = (183, 65, 14).try_into();
+        assert!(c.is_ok());
+        assert_eq!(
+            c.unwrap(),
+            Color {
+                red: 183,
+                green: 65,
+                blue: 14
+            }
+        );
+    }
+    #[test]
+    fn test_array_out_of_range_positive() {
+        let c: Result<Color, _> = [1000, 10000, 256].try_into();
+        assert_eq!(c, Err(IntoColorError::IntConversion));
+    }
+    #[test]
+    fn test_array_out_of_range_negative() {
+        let c: Result<Color, _> = [-10, -256, -1].try_into();
+        assert_eq!(c, Err(IntoColorError::IntConversion));
+    }
+    #[test]
+    fn test_array_sum() {
+        let c: Result<Color, _> = [-1, 255, 255].try_into();
+        assert_eq!(c, Err(IntoColorError::IntConversion));
+    }
+    #[test]
+    fn test_array_correct() {
+        let c: Result<Color, _> = [183, 65, 14].try_into();
+        assert!(c.is_ok());
+        assert_eq!(
+            c.unwrap(),
+            Color {
+                red: 183,
+                green: 65,
+                blue: 14
+            }
+        );
+    }
+    #[test]
+    fn test_slice_out_of_range_positive() {
+        let arr = [10000, 256, 1000];
+        assert_eq!(
+            Color::try_from(&arr[..]),
+            Err(IntoColorError::IntConversion)
+        );
+    }
+    #[test]
+    fn test_slice_out_of_range_negative() {
+        let arr = [-256, -1, -10];
+        assert_eq!(
+            Color::try_from(&arr[..]),
+            Err(IntoColorError::IntConversion)
+        );
+    }
+    #[test]
+    fn test_slice_sum() {
+        let arr = [-1, 255, 255];
+        assert_eq!(
+            Color::try_from(&arr[..]),
+            Err(IntoColorError::IntConversion)
+        );
+    }
+    #[test]
+    fn test_slice_correct() {
+        let v = vec![183, 65, 14];
+        let c: Result<Color, _> = Color::try_from(&v[..]);
+        assert!(c.is_ok());
+        assert_eq!(
+            c.unwrap(),
+            Color {
+                red: 183,
+                green: 65,
+                blue: 14
+            }
+        );
+    }
+    #[test]
+    fn test_slice_excess_length() {
+        let v = vec![0, 0, 0, 0];
+        assert_eq!(Color::try_from(&v[..]), Err(IntoColorError::BadLen));
+    }
+    #[test]
+    fn test_slice_insufficient_length() {
+        let v = vec![0, 0];
+        assert_eq!(Color::try_from(&v[..]), Err(IntoColorError::BadLen));
+    }
+}

exercises/conversions/using_as.rs

@@ -0,0 +1,28 @@
+// Type casting in Rust is done via the usage of the `as` operator.
+// Please note that the `as` operator is not only used when type casting.
+// It also helps with renaming imports.
+//
+// The goal is to make sure that the division does not fail to compile
+// and returns the proper type.
+
+// I AM NOT DONE
+
+fn average(values: &[f64]) -> f64 {
+    let total = values.iter().fold(0.0, |a, b| a + b);
+    total / values.len()
+}
+
+fn main() {
+    let values = [3.5, 0.3, 13.0, 11.7];
+    println!("{}", average(&values));
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn returns_proper_type_and_value() {
+        assert_eq!(average(&[3.5, 0.3, 13.0, 11.7]), 7.125);
+    }
+}

exercises/enums/README.md

@@ -1,7 +1,10 @@
-### Enums
+# Enums
 
-Rust allows you to define a type called `enums` which allow you to enumerate possible values. In combination with enums, we have the concept of `pattern matching` in Rust, which makes it easy to run different code for different values of an enumeration. Enums, while available in many languages, Rust's enums are most similar to `algebraic data types` in functional languages, such as F#, OCaml, and Haskell.
+Rust allows you to define types called "enums" which enumerate possible values.
+Enums are a feature in many languages, but their capabilities differ in each language. Rust’s enums are most similar to algebraic data types in functional languages, such as F#, OCaml, and Haskell.
+Useful in combination with enums is Rust's "pattern matching" facility, which makes it easy to run different code for different values of an enumeration.
 
-#### Book Sections
+## Further information
 
 - [Enums](https://doc.rust-lang.org/book/ch06-00-enums.html)
+- [Pattern syntax](https://doc.rust-lang.org/book/ch18-03-pattern-syntax.html)

exercises/enums/enums2.rs

@@ -16,10 +16,10 @@ impl Message {
 
 fn main() {
     let messages = [
-        Message::Move{ x: 10, y: 30 },
+        Message::Move { x: 10, y: 30 },
         Message::Echo(String::from("hello world")),
         Message::ChangeColor(200, 255, 255),
-        Message::Quit
+        Message::Quit,
     ];
 
     for message in &messages {

exercises/enums/enums3.rs

@@ -9,13 +9,13 @@ enum Message {
 
 struct Point {
     x: u8,
-    y: u8
+    y: u8,
 }
 
 struct State {
     color: (u8, u8, u8),
     position: Point,
-    quit: bool
+    quit: bool,
 }
 
 impl State {
@@ -46,14 +46,14 @@ mod tests {
 
     #[test]
     fn test_match_message_call() {
-        let mut state = State{
+        let mut state = State {
             quit: false,
-            position: Point{ x: 0, y: 0 },
-            color: (0, 0, 0)
+            position: Point { x: 0, y: 0 },
+            color: (0, 0, 0),
         };
-        state.process(Message::ChangeColor(255, 0, 255));
+        state.process(Message::ChangeColor((255, 0, 255)));
         state.process(Message::Echo(String::from("hello world")));
-        state.process(Message::Move{ x: 10, y: 15 });
+        state.process(Message::Move(Point { x: 10, y: 15 }));
         state.process(Message::Quit);
 
         assert_eq!(state.color, (255, 0, 255));
@@ -61,5 +61,4 @@ mod tests {
         assert_eq!(state.position.y, 15);
         assert_eq!(state.quit, true);
     }
-
 }

exercises/enums/mod.rs

@@ -0,0 +1,3 @@
+mod enums1;
+mod enums2;
+mod enums3;

exercises/error_handling/README.md

@@ -1,5 +1,11 @@
-For this exercise check out the sections:
-- [Error Handling](https://doc.rust-lang.org/book/ch09-02-recoverable-errors-with-result.html) 
-- [Generics](https://doc.rust-lang.org/book/ch10-01-syntax.html) 
+# Error handling
+Most errors aren’t serious enough to require the program to stop entirely. 
+Sometimes, when a function fails, it’s for a reason that you can easily interpret and respond to.
+For example, if you try to open a file and that operation fails because the file doesn’t exist, you might want to create the file instead of terminating the process.
 
-of the Rust Book.
+## Further information
+
+- [Error Handling](https://doc.rust-lang.org/book/ch09-02-recoverable-errors-with-result.html)
+- [Generics](https://doc.rust-lang.org/book/ch10-01-syntax.html)
+- [Result](https://doc.rust-lang.org/rust-by-example/error/result.html)
+- [Boxing errors](https://doc.rust-lang.org/rust-by-example/error/multiple_error_types/boxing_errors.html)

exercises/error_handling/errors1.rs

@@ -1,9 +1,8 @@
 // errors1.rs
 // This function refuses to generate text to be printed on a nametag if
 // you pass it an empty string. It'd be nicer if it explained what the problem
-// was, instead of just sometimes returning `None`. The 2nd test currently
-// does not compile or pass, but it illustrates the behavior we would like
-// this function to have.
+// was, instead of just sometimes returning `None`. Thankfully, Rust has a similar
+// construct to `Option` that can be used to express error conditions. Let's use it!
 // Execute `rustlings hint errors1` for hints!
 
 // I AM NOT DONE
@@ -21,14 +20,11 @@ pub fn generate_nametag_text(name: String) -> Option<String> {
 mod tests {
     use super::*;
 
-    // This test passes initially if you comment out the 2nd test.
-    // You'll need to update what this test expects when you change
-    // the function under test!
     #[test]
     fn generates_nametag_text_for_a_nonempty_name() {
         assert_eq!(
             generate_nametag_text("Beyoncé".into()),
-            Some("Hi! My name is Beyoncé".into())
+            Ok("Hi! My name is Beyoncé".into())
         );
     }
 
@@ -36,6 +32,7 @@ mod tests {
     fn explains_why_generating_nametag_text_fails() {
         assert_eq!(
             generate_nametag_text("".into()),
+            // Don't change this line
             Err("`name` was empty; it must be nonempty.".into())
         );
     }

exercises/error_handling/errors4.rs

@@ -1,5 +1,5 @@
-// result1.rs
-// Make this test pass! Execute `rustlings hint result1` for hints :)
+// errors4.rs
+// Make this test pass! Execute `rustlings hint errors4` for hints :)
 
 // I AM NOT DONE
 

exercises/error_handling/errors5.rs

@@ -0,0 +1,53 @@
+// errors5.rs
+
+// This program uses a completed version of the code from errors4.
+// It won't compile right now! Why?
+// Execute `rustlings hint errors5` for hints!
+
+// I AM NOT DONE
+
+use std::error;
+use std::fmt;
+use std::num::ParseIntError;
+
+// TODO: update the return type of `main()` to make this compile.
+fn main() -> Result<(), ParseIntError> {
+    let pretend_user_input = "42";
+    let x: i64 = pretend_user_input.parse()?;
+    println!("output={:?}", PositiveNonzeroInteger::new(x)?);
+    Ok(())
+}
+
+// Don't change anything below this line.
+
+#[derive(PartialEq, Debug)]
+struct PositiveNonzeroInteger(u64);
+
+#[derive(PartialEq, Debug)]
+enum CreationError {
+    Negative,
+    Zero,
+}
+
+impl PositiveNonzeroInteger {
+    fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
+        match value {
+            x if x < 0 => Err(CreationError::Negative),
+            x if x == 0 => Err(CreationError::Zero),
+            x => Ok(PositiveNonzeroInteger(x as u64))
+        }
+    }
+}
+
+// This is required so that `CreationError` can implement `error::Error`.
+impl fmt::Display for CreationError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let description = match *self {
+            CreationError::Negative => "number is negative",
+            CreationError::Zero => "number is zero",
+        };
+        f.write_str(description)
+    }
+}
+
+impl error::Error for CreationError {}

exercises/error_handling/errors6.rs

@@ -0,0 +1,92 @@
+// errors6.rs
+
+// Using catch-all error types like `Box<dyn error::Error>` isn't recommended
+// for library code, where callers might want to make decisions based on the
+// error content, instead of printing it out or propagating it further. Here,
+// we define a custom error type to make it possible for callers to decide
+// what to do next when our function returns an error.
+
+// Make these tests pass! Execute `rustlings hint errors6` for hints :)
+
+// I AM NOT DONE
+
+use std::num::ParseIntError;
+
+// This is a custom error type that we will be using in `parse_pos_nonzero()`.
+#[derive(PartialEq, Debug)]
+enum ParsePosNonzeroError {
+    Creation(CreationError),
+    ParseInt(ParseIntError)
+}
+
+impl ParsePosNonzeroError {
+    // TODO: add another error conversion function here.
+}
+
+fn parse_pos_nonzero(s: &str)
+    -> Result<PositiveNonzeroInteger, ParsePosNonzeroError>
+{
+    // TODO: change this to return an appropriate error instead of panicking
+    // when `parse()` returns an error.
+    let x: i64 = s.parse().unwrap();
+    PositiveNonzeroInteger::new(x)
+        .map_err(ParsePosNonzeroError::from_creation)
+}
+
+// Don't change anything below this line.
+
+#[derive(PartialEq, Debug)]
+struct PositiveNonzeroInteger(u64);
+
+#[derive(PartialEq, Debug)]
+enum CreationError {
+    Negative,
+    Zero,
+}
+
+impl PositiveNonzeroInteger {
+    fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
+        match value {
+            x if x < 0 => Err(CreationError::Negative),
+            x if x == 0 => Err(CreationError::Zero),
+            x => Ok(PositiveNonzeroInteger(x as u64))
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_parse_error() {
+        // We can't construct a ParseIntError, so we have to pattern match.
+        assert!(matches!(
+            parse_pos_nonzero("not a number"),
+            Err(ParsePosNonzeroError::ParseInt(_))
+        ));
+    }
+
+    #[test]
+    fn test_negative() {
+        assert_eq!(
+            parse_pos_nonzero("-555"),
+            Err(ParsePosNonzeroError::Creation(CreationError::Negative))
+        );
+    }
+
+    #[test]
+    fn test_zero() {
+        assert_eq!(
+            parse_pos_nonzero("0"),
+            Err(ParsePosNonzeroError::Creation(CreationError::Zero))
+        );
+    }
+
+    #[test]
+    fn test_positive() {
+        let x = PositiveNonzeroInteger::new(42);
+        assert!(x.is_ok());
+        assert_eq!(parse_pos_nonzero("42"), Ok(x.unwrap()));
+    }
+}

exercises/error_handling/errorsn.rs

@@ -1,114 +0,0 @@
-// errorsn.rs
-// This is a bigger error exercise than the previous ones!
-// You can do it! :)
-//
-// Edit the `read_and_validate` function so that it compiles and
-// passes the tests... so many things could go wrong!
-//
-// - Reading from stdin could produce an io::Error
-// - Parsing the input could produce a num::ParseIntError
-// - Validating the input could produce a CreationError (defined below)
-//
-// How can we lump these errors into one general error? That is, what
-// type goes where the question marks are, and how do we return
-// that type from the body of read_and_validate?
-//
-// Execute `rustlings hint errorsn` for hints :)
-
-// I AM NOT DONE
-
-use std::error;
-use std::fmt;
-use std::io;
-
-// PositiveNonzeroInteger is a struct defined below the tests.
-fn read_and_validate(b: &mut dyn io::BufRead) -> Result<PositiveNonzeroInteger, ???> {
-    let mut line = String::new();
-    b.read_line(&mut line);
-    let num: i64 = line.trim().parse();
-    let answer = PositiveNonzeroInteger::new(num);
-    answer
-}
-
-// This is a test helper function that turns a &str into a BufReader.
-fn test_with_str(s: &str) -> Result<PositiveNonzeroInteger, Box<dyn error::Error>> {
-    let mut b = io::BufReader::new(s.as_bytes());
-    read_and_validate(&mut b)
-}
-
-#[test]
-fn test_success() {
-    let x = test_with_str("42\n");
-    assert_eq!(PositiveNonzeroInteger(42), x.unwrap());
-}
-
-#[test]
-fn test_not_num() {
-    let x = test_with_str("eleven billion\n");
-    assert!(x.is_err());
-}
-
-#[test]
-fn test_non_positive() {
-    let x = test_with_str("-40\n");
-    assert!(x.is_err());
-}
-
-#[test]
-fn test_ioerror() {
-    struct Broken;
-    impl io::Read for Broken {
-        fn read(&mut self, _buf: &mut [u8]) -> io::Result<usize> {
-            Err(io::Error::new(io::ErrorKind::BrokenPipe, "uh-oh!"))
-        }
-    }
-    let mut b = io::BufReader::new(Broken);
-    assert!(read_and_validate(&mut b).is_err());
-    assert_eq!("uh-oh!", read_and_validate(&mut b).unwrap_err().to_string());
-}
-
-#[derive(PartialEq, Debug)]
-struct PositiveNonzeroInteger(u64);
-
-impl PositiveNonzeroInteger {
-    fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
-        if value == 0 {
-            Err(CreationError::Zero)
-        } else if value < 0 {
-            Err(CreationError::Negative)
-        } else {
-            Ok(PositiveNonzeroInteger(value as u64))
-        }
-    }
-}
-
-#[test]
-fn test_positive_nonzero_integer_creation() {
-    assert!(PositiveNonzeroInteger::new(10).is_ok());
-    assert_eq!(
-        Err(CreationError::Negative),
-        PositiveNonzeroInteger::new(-10)
-    );
-    assert_eq!(Err(CreationError::Zero), PositiveNonzeroInteger::new(0));
-}
-
-#[derive(PartialEq, Debug)]
-enum CreationError {
-    Negative,
-    Zero,
-}
-
-impl fmt::Display for CreationError {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.write_str((self as &dyn error::Error).description())
-    }
-}
-
-impl error::Error for CreationError {
-    fn description(&self) -> &str {
-        match *self {
-            CreationError::Negative => "Negative",
-            CreationError::Zero => "Zero",
-        }
-    }
-}

exercises/error_handling/mod.rs

@@ -0,0 +1,6 @@
+mod errors1;
+mod errors2;
+mod errors3;
+mod errors4;
+mod errors5;
+mod errors6;

exercises/error_handling/option1.rs

@@ -1,31 +0,0 @@
-// option1.rs
-// This example panics because the second time it calls `pop`, the `vec`
-// is empty, so `pop` returns `None`, and `unwrap` panics if it's called
-// on `None`. Handle this in a more graceful way than calling `unwrap`!
-// Execute `rustlings hint option1` for hints :)
-
-// I AM NOT DONE
-
-pub fn pop_too_much() -> bool {
-    let mut list = vec![3];
-
-    let last = list.pop().unwrap();
-    println!("The last item in the list is {:?}", last);
-
-    let second_to_last = list.pop().unwrap();
-    println!(
-        "The second-to-last item in the list is {:?}",
-        second_to_last
-    );
-    true
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn should_not_panic() {
-        assert!(pop_too_much());
-    }
-}

exercises/functions/README.md

@@ -1,7 +1,7 @@
-### Functions
+# Functions
 
 Here, you'll learn how to write functions and how Rust's compiler can trace things way back.
 
-#### Book Sections
+## Further information
 
 - [How Functions Work](https://doc.rust-lang.org/book/ch03-03-how-functions-work.html)

exercises/functions/functions2.rs

@@ -7,7 +7,7 @@ fn main() {
     call_me(3);
 }
 
-fn call_me(num) {
+fn call_me(num:) {
     for i in 0..num {
         println!("Ring! Call number {}", i + 1);
     }

exercises/functions/functions3.rs

@@ -7,7 +7,7 @@ fn main() {
     call_me();
 }
 
-fn call_me(num: i32) {
+fn call_me(num: u32) {
     for i in 0..num {
         println!("Ring! Call number {}", i + 1);
     }

exercises/functions/functions4.rs

@@ -2,7 +2,7 @@
 // Make me compile! Execute `rustlings hint functions4` for hints :)
 
 // This store is having a sale where if the price is an even number, you get
-// 10 (money unit) off, but if it's an odd number, it's 3 (money unit) less.
+// 10 Rustbucks off, but if it's an odd number, it's 3 Rustbucks off.
 
 // I AM NOT DONE
 

exercises/functions/mod.rs

@@ -0,0 +1,5 @@
+mod functions1;
+mod functions2;
+mod functions3;
+mod functions4;
+mod functions5;

exercises/generics/README.md

@@ -0,0 +1,11 @@
+# Generics
+
+Generics is the topic of generalizing types and functionalities to broader cases.
+This is extremely useful for reducing code duplication in many ways, but can call for rather involving syntax.
+Namely, being generic requires taking great care to specify over which types a generic type is actually considered valid.
+The simplest and most common use of generics is for type parameters.
+
+## Further information
+
+- [Generic Data Types](https://doc.rust-lang.org/stable/book/ch10-01-syntax.html)
+- [Bounds](https://doc.rust-lang.org/rust-by-example/generics/bounds.html)

exercises/generics/generics1.rs

@@ -0,0 +1,11 @@
+// This shopping list program isn't compiling!
+// Use your knowledge of generics to fix it.
+
+// Execute `rustlings hint generics1` for hints!
+
+// I AM NOT DONE
+
+fn main() {
+    let mut shopping_list: Vec<?> = Vec::new();
+    shopping_list.push("milk");
+}

exercises/generics/generics2.rs

@@ -0,0 +1,31 @@
+// This powerful wrapper provides the ability to store a positive integer value.
+// Rewrite it using generics so that it supports wrapping ANY type.
+
+// Execute `rustlings hint generics2` for hints!
+
+// I AM NOT DONE
+
+struct Wrapper {
+    value: u32,
+}
+
+impl Wrapper {
+    pub fn new(value: u32) -> Self {
+        Wrapper { value }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn store_u32_in_wrapper() {
+        assert_eq!(Wrapper::new(42).value, 42);
+    }
+
+    #[test]
+    fn store_str_in_wrapper() {
+        assert_eq!(Wrapper::new("Foo").value, "Foo");
+    }
+}

exercises/generics/generics3.rs

@@ -0,0 +1,58 @@
+// An imaginary magical school has a new report card generation system written in Rust!
+// Currently the system only supports creating report cards where the student's grade
+// is represented numerically (e.g. 1.0 -> 5.5).
+// However, the school also issues alphabetical grades (A+ -> F-) and needs
+// to be able to print both types of report card!
+
+// Make the necessary code changes in the struct ReportCard and the impl block
+// to support alphabetical report cards. Change the Grade in the second test to "A+"
+// to show that your changes allow alphabetical grades.
+
+// Execute 'rustlings hint generics3' for hints!
+
+// I AM NOT DONE
+
+pub struct ReportCard {
+    pub grade: f32,
+    pub student_name: String,
+    pub student_age: u8,
+}
+
+impl ReportCard {
+    pub fn print(&self) -> String {
+        format!("{} ({}) - achieved a grade of {}",
+            &self.student_name, &self.student_age, &self.grade)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn generate_numeric_report_card() {
+        let report_card = ReportCard {
+            grade: 2.1,
+            student_name: "Tom Wriggle".to_string(),
+            student_age: 12,
+        };
+        assert_eq!(
+            report_card.print(),
+            "Tom Wriggle (12) - achieved a grade of 2.1"
+        );
+    }
+
+    #[test]
+    fn generate_alphabetic_report_card() {
+        // TODO: Make sure to change the grade here after you finish the exercise.
+        let report_card = ReportCard {
+            grade: 2.1,
+            student_name: "Gary Plotter".to_string(),
+            student_age: 11,
+        };
+        assert_eq!(
+            report_card.print(),
+            "Gary Plotter (11) - achieved a grade of A+"
+        );
+    }
+}

exercises/generics/mod.rs

@@ -0,0 +1,3 @@
+mod generics1;
+mod generics2;
+mod generics3;

exercises/if/README.md

@@ -1,7 +1,7 @@
-### If
+# If
 
 `if`, the most basic type of control flow, is what you'll learn here.
 
-#### Book Sections
+## Further information
 
 - [Control Flow - if expressions](https://doc.rust-lang.org/book/ch03-05-control-flow.html#if-expressions)

exercises/if/if2.rs

@@ -0,0 +1,36 @@
+// if2.rs
+
+// Step 1: Make me compile!
+// Step 2: Get the bar_for_fuzz and default_to_baz tests passing!
+// Execute the command `rustlings hint if2` if you want a hint :)
+
+// I AM NOT DONE
+
+pub fn fizz_if_foo(fizzish: &str) -> &str {
+    if fizzish == "fizz" {
+        "foo"
+    } else {
+        1
+    }
+}
+
+// No test changes needed!
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn foo_for_fizz() {
+        assert_eq!(fizz_if_foo("fizz"), "foo")
+    }
+
+    #[test]
+    fn bar_for_fuzz() {
+        assert_eq!(fizz_if_foo("fuzz"), "bar")
+    }
+
+    #[test]
+    fn default_to_baz() {
+        assert_eq!(fizz_if_foo("literally anything"), "baz")
+    }
+}

exercises/if/mod.rs

@@ -0,0 +1,2 @@
+mod if1;
+mod if2;

exercises/intro/README.md

@@ -0,0 +1,8 @@
+# Intro
+
+Rust uses the `print!` and `println!` macros to print text to the console.
+
+## Further information
+
+- [Hello World](https://doc.rust-lang.org/rust-by-example/hello.html)
+- [Formatted print](https://doc.rust-lang.org/rust-by-example/hello/print.html)

exercises/intro/intro1.rs

@@ -0,0 +1,23 @@
+// intro1.rs
+// About this `I AM NOT DONE` thing:
+// We sometimes encourage you to keep trying things on a given exercise, even
+// after you already figured it out. If you got everything working and feel
+// ready for the next exercise, remove the `I AM NOT DONE` comment below.
+// Execute the command `rustlings hint intro1` for a hint.
+
+// I AM NOT DONE
+
+fn main() {
+    println!("Hello and");
+    println!(r#"       welcome to...                      "#);
+    println!(r#"                 _   _ _                  "#);
+    println!(r#"  _ __ _   _ ___| |_| (_)_ __   __ _ ___  "#);
+    println!(r#" | '__| | | / __| __| | | '_ \ / _` / __| "#);
+    println!(r#" | |  | |_| \__ \ |_| | | | | | (_| \__ \ "#);
+    println!(r#" |_|   \__,_|___/\__|_|_|_| |_|\__, |___/ "#);
+    println!(r#"                               |___/      "#);
+    println!();
+    println!("This exercise compiles successfully. The remaining exercises contain a compiler");
+    println!("or logic error. The central concept behind Rustlings is to fix these errors and");
+    println!("solve the exercises. Good luck!");
+}

exercises/intro/intro2.rs

@@ -0,0 +1,9 @@
+// intro2.rs
+// Make the code print a greeting to the world.
+// Execute `rustlings hint intro2` for a hint.
+
+// I AM NOT DONE
+
+fn main() {
+    println!("Hello {}!");
+}

exercises/intro/mod.rs

@@ -0,0 +1,2 @@
+mod intro1;
+mod intro2;

exercises/macros/README.md

@@ -1,10 +1,10 @@
-### Macros
+# Macros
 
 Rust's macro system is very powerful, but also kind of difficult to wrap your
 head around. We're not going to teach you how to write your own fully-featured
-modules, instead we'll show you how to use and create them.
+macros. Instead, we'll show you how to use and create them.
 
-#### Book Sections
+## Further information
 
 - [Macros](https://doc.rust-lang.org/book/ch19-06-macros.html)
 - [The Little Book of Rust Macros](https://danielkeep.github.io/tlborm/book/index.html)

exercises/macros/mod.rs

@@ -0,0 +1,4 @@
+mod macros1;
+mod macros2;
+mod macros3;
+mod macros4;

exercises/mod.rs

@@ -0,0 +1,26 @@
+mod advanced_errors;
+mod clippy;
+mod collections;
+mod conversions;
+mod enums;
+mod error_handling;
+mod functions;
+mod generics;
+mod r#if;
+mod intro;
+mod macros;
+mod modules;
+mod move_semantics;
+mod option;
+mod primitive_types;
+mod quiz1;
+mod quiz2;
+mod quiz3;
+mod quiz4;
+mod standard_library_types;
+mod strings;
+mod structs;
+mod tests;
+mod threads;
+mod traits;
+mod variables;

exercises/modules/README.md

@@ -1,7 +1,7 @@
-### Modules
+# Modules
 
 In this section we'll give you an introduction to Rust's module system.
 
-#### Book Sections
+## Further information
 
-- [The Module System](https://doc.rust-lang.org/book/ch07-02-defining-modules-to-control-scope-and-privacy.html)
+- [The Module System](https://doc.rust-lang.org/book/ch07-00-managing-growing-projects-with-packages-crates-and-modules.html)

exercises/modules/mod.rs

@@ -0,0 +1,3 @@
+mod modules1;
+mod modules2;
+mod modules3;

exercises/modules/modules1.rs

@@ -4,7 +4,13 @@
 // I AM NOT DONE
 
 mod sausage_factory {
+    // Don't let anybody outside of this module see this!
+    fn get_secret_recipe() -> String {
+        String::from("Ginger")
+    }
+
     fn make_sausage() {
+        get_secret_recipe();
         println!("sausage!");
     }
 }

exercises/modules/modules2.rs

@@ -1,11 +1,15 @@
 // modules2.rs
+// You can bring module paths into scopes and provide new names for them with the
+// 'use' and 'as' keywords. Fix these 'use' statements to make the code compile.
 // Make me compile! Execute `rustlings hint modules2` for hints :)
 
 // I AM NOT DONE
 
 mod delicious_snacks {
-    use self::fruits::PEAR as fruit;
-    use self::veggies::CUCUMBER as veggie;
+
+    // TODO: Fix these use statements
+    use self::fruits::PEAR as ???
+    use self::veggies::CUCUMBER as ???
 
     mod fruits {
         pub const PEAR: &'static str = "Pear";

exercises/modules/modules3.rs

@@ -0,0 +1,18 @@
+// modules3.rs
+// You can use the 'use' keyword to bring module paths from modules from anywhere
+// and especially from the Rust standard library into your scope.
+// Bring SystemTime and UNIX_EPOCH
+// from the std::time module. Bonus style points if you can do it with one line!
+// Make me compile! Execute `rustlings hint modules3` for hints :)
+
+// I AM NOT DONE
+
+// TODO: Complete this use statement
+use ???
+
+fn main() {
+    match SystemTime::now().duration_since(UNIX_EPOCH) {
+        Ok(n) => println!("1970-01-01 00:00:00 UTC was {} seconds ago!", n.as_secs()),
+        Err(_) => panic!("SystemTime before UNIX EPOCH!"),
+    }
+}

exercises/move_semantics/README.md

@@ -1,8 +1,8 @@
-### Move Semantics
+# Move Semantics
 
 These exercises are adapted from [pnkfelix](https://github.com/pnkfelix)'s [Rust Tutorial](https://pnkfelix.github.io/rust-examples-icfp2014/) -- Thank you Felix!!!
 
-#### Book Sections
+## Further information
 
 For this section, the book links are especially important.
 

exercises/move_semantics/mod.rs

@@ -0,0 +1,6 @@
+mod move_semantics1;
+mod move_semantics2;
+mod move_semantics3;
+mod move_semantics4;
+mod move_semantics5;
+mod move_semantics6;

exercises/move_semantics/move_semantics2.rs

@@ -1,5 +1,5 @@
 // move_semantics2.rs
-// Make me compile without changing line 10!
+// Make me compile without changing line 13 or moving line 10!
 // Execute `rustlings hint move_semantics2` for hints :)
 
 // I AM NOT DONE

exercises/move_semantics/move_semantics4.rs

@@ -1,6 +1,6 @@
 // move_semantics4.rs
 // Refactor this code so that instead of having `vec0` and creating the vector
-// in `fn main`, we instead create it within `fn fill_vec` and transfer the
+// in `fn main`, we create it within `fn fill_vec` and transfer the
 // freshly created vector from fill_vec to its caller.
 // Execute `rustlings hint move_semantics4` for hints!
 
@@ -18,7 +18,7 @@ fn main() {
     println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
 }
 
-// `fill_vec()` no longer take `vec: Vec<i32>` as argument
+// `fill_vec()` no longer takes `vec: Vec<i32>` as argument
 fn fill_vec() -> Vec<i32> {
     let mut vec = vec;
 

exercises/move_semantics/move_semantics5.rs

@@ -0,0 +1,15 @@
+// move_semantics5.rs
+// Make me compile only by reordering the lines in `main()`, but without
+// adding, changing or removing any of them.
+// Execute `rustlings hint move_semantics5` for hints :)
+
+// I AM NOT DONE
+
+fn main() {
+    let mut x = 100;
+    let y = &mut x;
+    let z = &mut x;
+    *y += 100;
+    *z += 1000;
+    assert_eq!(x, 1200);
+}

exercises/move_semantics/move_semantics6.rs

@@ -0,0 +1,25 @@
+// move_semantics6.rs
+// Make me compile! `rustlings hint move_semantics6` for hints
+// You can't change anything except adding or removing references
+
+// I AM NOT DONE
+
+fn main() {
+    let data = "Rust is great!".to_string();
+
+    get_char(data);
+
+    string_uppercase(&data);
+}
+
+// Should not take ownership
+fn get_char(data: String) -> char {
+    data.chars().last().unwrap()
+}
+
+// Should take ownership
+fn string_uppercase(mut data: &String) {
+    data = &data.to_uppercase();
+
+    println!("{}", data);
+}

exercises/option/README.md

@@ -0,0 +1,20 @@
+# Option
+
+Type Option represents an optional value: every Option is either Some and contains a value, or None, and does not. 
+Option types are very common in Rust code, as they have a number of uses:
+- Initial values
+- Return values for functions that are not defined over their entire input range (partial functions)
+- Return value for otherwise reporting simple errors, where None is returned on error
+- Optional struct fields
+- Struct fields that can be loaned or "taken"
+- Optional function arguments
+- Nullable pointers
+- Swapping things out of difficult situations
+
+## Further Information
+
+- [Option Enum Format](https://doc.rust-lang.org/stable/book/ch10-01-syntax.html#in-enum-definitions)
+- [Option Module Documentation](https://doc.rust-lang.org/std/option/)
+- [Option Enum Documentation](https://doc.rust-lang.org/std/option/enum.Option.html)
+- [if let](https://doc.rust-lang.org/rust-by-example/flow_control/if_let.html)
+- [while let](https://doc.rust-lang.org/rust-by-example/flow_control/while_let.html)

exercises/option/mod.rs

@@ -0,0 +1,3 @@
+mod option1;
+mod option2;
+mod option3;

exercises/option/option1.rs

@@ -0,0 +1,23 @@
+// option1.rs
+// Make me compile! Execute `rustlings hint option1` for hints
+
+// I AM NOT DONE
+
+// you can modify anything EXCEPT for this function's signature
+fn print_number(maybe_number: Option<u16>) {
+    println!("printing: {}", maybe_number.unwrap());
+}
+
+fn main() {
+    print_number(13);
+    print_number(99);
+
+    let mut numbers: [Option<u16>; 5];
+    for iter in 0..5 {
+        let number_to_add: u16 = {
+            ((iter * 1235) + 2) / (4 * 16)
+        };
+
+        numbers[iter as usize] = number_to_add;
+    }
+}

exercises/option/option2.rs

@@ -0,0 +1,25 @@
+// option2.rs
+// Make me compile! Execute `rustlings hint option2` for hints
+
+// I AM NOT DONE
+
+fn main() {
+    let optional_word = Some(String::from("rustlings"));
+    // TODO: Make this an if let statement whose value is "Some" type
+    word = optional_word {
+        println!("The word is: {}", word);
+    } else {
+        println!("The optional word doesn't contain anything");
+    }
+
+    let mut optional_integers_vec: Vec<Option<i8>> = Vec::new();
+    for x in 1..10 {
+        optional_integers_vec.push(Some(x));
+    }
+
+    // TODO: make this a while let statement - remember that vector.pop also adds another layer of Option<T>
+    // You can stack `Option<T>`'s into while let and if let
+    integer = optional_integers_vec.pop() {
+        println!("current value: {}", integer);
+    }
+}

exercises/option/option3.rs

@@ -0,0 +1,19 @@
+// option3.rs
+// Make me compile! Execute `rustlings hint option3` for hints
+
+// I AM NOT DONE
+
+struct Point {
+    x: i32,
+    y: i32,
+}
+
+fn main() {
+    let y: Option<Point> = Some(Point { x: 100, y: 200 });
+
+    match y {
+        Some(p) => println!("Co-ordinates are {},{} ", p.x, p.y),
+        _ => println!("no match"),
+    }
+    y; // Fix without deleting this line.
+}

exercises/primitive_types/README.md

@@ -1,9 +1,9 @@
-### Primitive Types
+# Primitive Types
 
 Rust has a couple of basic types that are directly implemented into the
 compiler. In this section, we'll go through the most important ones.
 
-#### Book Sections
+## Further information
 
 - [Data Types](https://doc.rust-lang.org/stable/book/ch03-02-data-types.html)
 - [The Slice Type](https://doc.rust-lang.org/stable/book/ch04-03-slices.html)

exercises/primitive_types/mod.rs

@@ -0,0 +1,6 @@
+mod primitive_types1;
+mod primitive_types2;
+mod primitive_types3;
+mod primitive_types4;
+mod primitive_types5;
+mod primitive_types6;

exercises/primitive_types/primitive_types3.rs

@@ -1,5 +1,5 @@
 // primitive_types3.rs
-// Create an array with at least 100 elements in it where the ??? is. 
+// Create an array with at least 100 elements in it where the ??? is.
 // Execute `rustlings hint primitive_types3` for hints!
 
 // I AM NOT DONE

exercises/primitive_types/primitive_types4.rs

@@ -1,11 +1,11 @@
 // primitive_types4.rs
-// Get a slice out of Array a where the ??? is so that the `if` statement
-// returns true. Execute `rustlings hint primitive_types4` for hints!!
+// Get a slice out of Array a where the ??? is so that the test passes.
+// Execute `rustlings hint primitive_types4` for hints!!
 
 // I AM NOT DONE
 
 #[test]
-fn main() {
+fn slice_out_of_array() {
     let a = [1, 2, 3, 4, 5];
 
     let nice_slice = ???

exercises/primitive_types/primitive_types6.rs

@@ -1,11 +1,16 @@
 // primitive_types6.rs
 // Use a tuple index to access the second element of `numbers`.
-// You can put this right into the `println!` where the ??? is.
+// You can put the expression for the second element where ??? is so that the test passes.
 // Execute `rustlings hint primitive_types6` for hints!
 
 // I AM NOT DONE
 
-fn main() {
+#[test]
+fn indexing_tuple() {
     let numbers = (1, 2, 3);
-    println!("The second number is {}", ???);
+    // Replace below ??? with the tuple indexing syntax.
+    let second = ???;
+
+    assert_eq!(2, second,
+        "This is not the 2nd number in the tuple!")
 }

exercises/quiz1.rs

@@ -0,0 +1,26 @@
+// quiz1.rs
+// This is a quiz for the following sections:
+// - Variables
+// - Functions
+// - If
+
+// Mary is buying apples. One apple usually costs 2 Rustbucks, but if you buy
+// more than 40 at once, each apple only costs 1! Write a function that calculates
+// the price of an order of apples given the quantity bought. No hints this time!
+
+// I AM NOT DONE
+
+// Put your function here!
+// fn calculate_apple_price {
+
+// Don't modify this function!
+#[test]
+fn verify_test() {
+    let price1 = calculate_apple_price(35);
+    let price2 = calculate_apple_price(40);
+    let price3 = calculate_apple_price(65);
+
+    assert_eq!(70, price1);
+    assert_eq!(80, price2);
+    assert_eq!(65, price3);
+}

exercises/quiz2.rs

@@ -0,0 +1,30 @@
+// quiz2.rs
+// This is a quiz for the following sections:
+// - Strings
+
+// Ok, here are a bunch of values-- some are `String`s, some are `&str`s. Your
+// task is to call one of these two functions on each value depending on what
+// you think each value is. That is, add either `string_slice` or `string`
+// before the parentheses on each line. If you're right, it will compile!
+
+// I AM NOT DONE
+
+fn string_slice(arg: &str) {
+    println!("{}", arg);
+}
+fn string(arg: String) {
+    println!("{}", arg);
+}
+
+fn main() {
+    ???("blue");
+    ???("red".to_string());
+    ???(String::from("hi"));
+    ???("rust is fun!".to_owned());
+    ???("nice weather".into());
+    ???(format!("Interpolation {}", "Station"));
+    ???(&String::from("abc")[0..1]);
+    ???("  hello there ".trim());
+    ???("Happy Monday!".to_string().replace("Mon", "Tues"));
+    ???("mY sHiFt KeY iS sTiCkY".to_lowercase());
+}

exercises/quiz3.rs

@@ -1,8 +1,8 @@
-// test3.rs
-// This is a test for the following sections:
+// quiz3.rs
+// This is a quiz for the following sections:
 // - Tests
 
-// This test isn't testing our function -- make it do that in such a way that
+// This quiz isn't testing our function -- make it do that in such a way that
 // the test passes. Then write a second test that tests that we get the result
 // we expect to get when we call `times_two` with a negative number.
 // No hints, you can do this :)
@@ -24,6 +24,7 @@ mod tests {
 
     #[test]
     fn returns_twice_of_negative_numbers() {
-        // TODO write an assert for `times_two(-4)`
+        // TODO replace unimplemented!() with an assert for `times_two(-4)`
+        unimplemented!()
     }
 }

exercises/quiz4.rs

@@ -0,0 +1,23 @@
+// quiz4.rs
+// This quiz covers the sections:
+// - Modules
+// - Macros
+
+// Write a macro that passes the quiz! No hints this time, you can do it!
+
+// I AM NOT DONE
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_my_macro_world() {
+        assert_eq!(my_macro!("world!"), "Hello world!");
+    }
+
+    #[test]
+    fn test_my_macro_goodbye() {
+        assert_eq!(my_macro!("goodbye!"), "Hello goodbye!");
+    }
+}

exercises/standard_library_types/README.md

@@ -1,5 +1,10 @@
-For the Arc exercise check out the chapter [Shared-State Concurrency](https://doc.rust-lang.org/book/ch16-03-shared-state.html) of the Rust Book.
+# Standard library types
 
-For the Iterator exercise check out the chapters [Iterator](https://doc.rust-lang.org/book/ch13-02-iterators.html) of the Rust Book and the [Iterator documentation](https://doc.rust-lang.org/stable/std/iter/).
-Do not adjust your monitors-- iterators 1 and 2 are indeed missing. Iterator 3 is a bit challenging so we're leaving space for some exercises to lead up to it!
+This section will teach you about Box, Shared-State Concurrency and Iterators.
 
+## Further information
+
+- [Using Box to Point to Data on the Heap](https://doc.rust-lang.org/book/ch15-01-box.html)
+- [Shared-State Concurrency](https://doc.rust-lang.org/book/ch16-03-shared-state.html)
+- [Iterator](https://doc.rust-lang.org/book/ch13-02-iterators.html)
+- [Iterator documentation](https://doc.rust-lang.org/stable/std/iter/)

exercises/standard_library_types/arc1.rs

@@ -1,11 +1,26 @@
 // arc1.rs
+// In this exercise, we are given a Vec of u32 called "numbers" with values ranging
+// from 0 to 99 -- [ 0, 1, 2, ..., 98, 99 ]
+// We would like to use this set of numbers within 8 different threads simultaneously.
+// Each thread is going to get the sum of every eighth value, with an offset.
+// The first thread (offset 0), will sum 0, 8, 16, ...
+// The second thread (offset 1), will sum 1, 9, 17, ...
+// The third thread (offset 2), will sum 2, 10, 18, ...
+// ...
+// The eighth thread (offset 7), will sum 7, 15, 23, ...
+
+// Because we are using threads, our values need to be thread-safe.  Therefore,
+// we are using Arc.  We need to make a change in each of the two TODOs.
+
+
 // Make this code compile by filling in a value for `shared_numbers` where the
-// TODO comment is and creating an initial binding for `child_numbers`
-// somewhere. Try not to create any copies of the `numbers` Vec!
-// Execute `rustlings help arc1` for hints :)
+// first TODO comment is, and create an initial binding for `child_numbers`
+// where the second TODO comment is. Try not to create any copies of the `numbers` Vec!
+// Execute `rustlings hint arc1` for hints :)
 
 // I AM NOT DONE
 
+#![forbid(unused_imports)] // Do not change this, (or the next) line.
 use std::sync::Arc;
 use std::thread;
 
@@ -15,12 +30,13 @@ fn main() {
     let mut joinhandles = Vec::new();
 
     for offset in 0..8 {
+        let child_numbers = // TODO
         joinhandles.push(thread::spawn(move || {
             let mut i = offset;
             let mut sum = 0;
             while i < child_numbers.len() {
                 sum += child_numbers[i];
-                i += 5;
+                i += 8;
             }
             println!("Sum of offset {} is {}", offset, sum);
         }));

exercises/standard_library_types/box1.rs

@@ -0,0 +1,56 @@
+// box1.rs
+//
+// At compile time, Rust needs to know how much space a type takes up. This becomes problematic
+// for recursive types, where a value can have as part of itself another value of the same type.
+// To get around the issue, we can use a `Box` - a smart pointer used to store data on the heap,
+// which also allows us to wrap a recursive type.
+//
+// The recursive type we're implementing in this exercise is the `cons list` - a data structure
+// frequently found in functional programming languages. Each item in a cons list contains two
+// elements: the value of the current item and the next item. The last item is a value called `Nil`.
+//
+// Step 1: use a `Box` in the enum definition to make the code compile
+// Step 2: create both empty and non-empty cons lists by replacing `unimplemented!()`
+//
+// Note: the tests should not be changed
+//
+// Execute `rustlings hint box1` for hints :)
+
+// I AM NOT DONE
+
+#[derive(PartialEq, Debug)]
+pub enum List {
+    Cons(i32, List),
+    Nil,
+}
+
+fn main() {
+    println!("This is an empty cons list: {:?}", create_empty_list());
+    println!(
+        "This is a non-empty cons list: {:?}",
+        create_non_empty_list()
+    );
+}
+
+pub fn create_empty_list() -> List {
+    unimplemented!()
+}
+
+pub fn create_non_empty_list() -> List {
+    unimplemented!()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_create_empty_list() {
+        assert_eq!(List::Nil, create_empty_list())
+    }
+
+    #[test]
+    fn test_create_non_empty_list() {
+        assert_ne!(create_empty_list(), create_non_empty_list())
+    }
+}

exercises/standard_library_types/iterators1.rs

@@ -0,0 +1,24 @@
+// iterators1.rs
+//
+//  Make me compile by filling in the `???`s
+//
+// When performing operations on elements within a collection, iterators are essential.
+// This module helps you get familiar with the structure of using an iterator and
+// how to go through elements within an iterable collection.
+//
+// Execute `rustlings hint iterators1` for hints :D
+
+// I AM NOT DONE
+
+fn main () {
+    let my_fav_fruits = vec!["banana", "custard apple", "avocado", "peach", "raspberry"];
+
+    let mut my_iterable_fav_fruits = ???;   // TODO: Step 1
+
+    assert_eq!(my_iterable_fav_fruits.next(), Some(&"banana"));
+    assert_eq!(my_iterable_fav_fruits.next(), ???);     // TODO: Step 2
+    assert_eq!(my_iterable_fav_fruits.next(), Some(&"avocado"));
+    assert_eq!(my_iterable_fav_fruits.next(), ???);     // TODO: Step 3
+    assert_eq!(my_iterable_fav_fruits.next(), Some(&"raspberry"));
+    assert_eq!(my_iterable_fav_fruits.next(), ???);     // TODO: Step 4
+}

exercises/standard_library_types/iterators2.rs

@@ -1,26 +1,41 @@
 // iterators2.rs
-// In this module, you'll learn some of unique advantages that iterators can offer
-// Step 1. Complete the `capitalize_first` function to pass the first two cases
-// Step 2. Apply the `capitalize_first` function to a vector of strings, ensuring that it returns a vector of strings as well
-// Step 3. Apply the `capitalize_first` function again to a list, but try and ensure it returns a single string
+// In this exercise, you'll learn some of the unique advantages that iterators
+// can offer. Follow the steps to complete the exercise.
 // As always, there are hints if you execute `rustlings hint iterators2`!
 
 // I AM NOT DONE
 
+// Step 1.
+// Complete the `capitalize_first` function.
+// "hello" -> "Hello"
 pub fn capitalize_first(input: &str) -> String {
     let mut c = input.chars();
     match c.next() {
         None => String::new(),
-        Some(first) => first.collect::<String>() + c.as_str(),
+        Some(first) => ???,
     }
 }
 
+// Step 2.
+// Apply the `capitalize_first` function to a slice of string slices.
+// Return a vector of strings.
+// ["hello", "world"] -> ["Hello", "World"]
+pub fn capitalize_words_vector(words: &[&str]) -> Vec<String> {
+    vec![]
+}
+
+// Step 3.
+// Apply the `capitalize_first` function again to a slice of string slices.
+// Return a single string.
+// ["hello", " ", "world"] -> "Hello World"
+pub fn capitalize_words_string(words: &[&str]) -> String {
+    String::new()
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
 
-    // Step 1.
-    // Tests that verify your `capitalize_first` function implementation
     #[test]
     fn test_success() {
         assert_eq!(capitalize_first("hello"), "Hello");
@@ -31,18 +46,15 @@ mod tests {
         assert_eq!(capitalize_first(""), "");
     }
 
-    // Step 2.
     #[test]
     fn test_iterate_string_vec() {
         let words = vec!["hello", "world"];
-        let capitalized_words: Vec<String> = // TODO
-        assert_eq!(capitalized_words, ["Hello", "World"]);
+        assert_eq!(capitalize_words_vector(&words), ["Hello", "World"]);
     }
 
     #[test]
     fn test_iterate_into_string() {
         let words = vec!["hello", " ", "world"];
-        let capitalized_words = // TODO
-        assert_eq!(capitalized_words, "Hello World");
+        assert_eq!(capitalize_words_string(&words), "Hello World");
     }
 }

exercises/standard_library_types/iterators3.rs

@@ -1,11 +1,10 @@
 // iterators3.rs
 // This is a bigger exercise than most of the others! You can do it!
 // Here is your mission, should you choose to accept it:
-// 1. Complete the divide function to get the first four tests to pass
-// 2. Uncomment the last two tests and get them to pass by filling in
-//    values for `x` using `division_results`.
+// 1. Complete the divide function to get the first four tests to pass.
+// 2. Get the remaining tests to pass by completing the result_with_list and
+//    list_of_results functions.
 // Execute `rustlings hint iterators3` to get some hints!
-// Have fun :-)
 
 // I AM NOT DONE
 
@@ -21,16 +20,28 @@ pub struct NotDivisibleError {
     divisor: i32,
 }
 
-// This function should calculate `a` divided by `b` if `a` is
-// evenly divisible by b.
-// Otherwise, it should return a suitable error.
+// Calculate `a` divided by `b` if `a` is evenly divisible by `b`.
+// Otherwise, return a suitable error.
 pub fn divide(a: i32, b: i32) -> Result<i32, DivisionError> {}
 
+// Complete the function and return a value of the correct type so the test passes.
+// Desired output: Ok([1, 11, 1426, 3])
+fn result_with_list() -> () {
+    let numbers = vec![27, 297, 38502, 81];
+    let division_results = numbers.into_iter().map(|n| divide(n, 27));
+}
+
+// Complete the function and return a value of the correct type so the test passes.
+// Desired output: [Ok(1), Ok(11), Ok(1426), Ok(3)]
+fn list_of_results() -> () {
+    let numbers = vec![27, 297, 38502, 81];
+    let division_results = numbers.into_iter().map(|n| divide(n, 27));
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
 
-    // Tests that verify your `divide` function implementation
     #[test]
     fn test_success() {
         assert_eq!(divide(81, 9), Ok(9));
@@ -57,22 +68,16 @@ mod tests {
         assert_eq!(divide(0, 81), Ok(0));
     }
 
-    // Iterator exercises using your `divide` function
-    /*
     #[test]
-    fn result_with_list() {
-        let numbers = vec![27, 297, 38502, 81];
-        let division_results = numbers.into_iter().map(|n| divide(n, 27));
-        let x //... Fill in here!
-        assert_eq!(format!("{:?}", x), "Ok([1, 11, 1426, 3])");
+    fn test_result_with_list() {
+        assert_eq!(format!("{:?}", result_with_list()), "Ok([1, 11, 1426, 3])");
     }
 
     #[test]
-    fn list_of_results() {
-        let numbers = vec![27, 297, 38502, 81];
-        let division_results = numbers.into_iter().map(|n| divide(n, 27));
-        let x //... Fill in here!
-        assert_eq!(format!("{:?}", x), "[Ok(1), Ok(11), Ok(1426), Ok(3)]");
+    fn test_list_of_results() {
+        assert_eq!(
+            format!("{:?}", list_of_results()),
+            "[Ok(1), Ok(11), Ok(1426), Ok(3)]"
+        );
     }
-    */
 }

exercises/standard_library_types/iterators4.rs

@@ -3,13 +3,13 @@
 // I AM NOT DONE
 
 pub fn factorial(num: u64) -> u64 {
-    // Complete this function to return factorial of num
+    // Complete this function to return the factorial of num
     // Do not use:
     // - return
-    // For extra fun don't use:
+    // Try not to use:
     // - imperative style loops (for, while)
     // - additional variables
-    // For the most fun don't use:
+    // For an extra challenge, don't use:
     // - recursion
     // Execute `rustlings hint iterators4` for hints.
 }

exercises/standard_library_types/iterators5.rs

@@ -0,0 +1,122 @@
+// iterators5.rs
+// Let's define a simple model to track Rustlings exercise progress. Progress
+// will be modelled using a hash map. The name of the exercise is the key and
+// the progress is the value. Two counting functions were created to count the
+// number of exercises with a given progress. These counting functions use
+// imperative style for loops. Recreate this counting functionality using
+// iterators. Only the two iterator methods (count_iterator and
+// count_collection_iterator) need to be modified.
+// Execute `rustlings hint iterators5` for hints.
+//
+// Make the code compile and the tests pass.
+
+// I AM NOT DONE
+
+use std::collections::HashMap;
+
+#[derive(Clone, Copy, PartialEq, Eq)]
+enum Progress {
+    None,
+    Some,
+    Complete,
+}
+
+fn count_for(map: &HashMap<String, Progress>, value: Progress) -> usize {
+    let mut count = 0;
+    for val in map.values() {
+        if val == &value {
+            count += 1;
+        }
+    }
+    count
+}
+
+fn count_iterator(map: &HashMap<String, Progress>, value: Progress) -> usize {
+    // map is a hashmap with String keys and Progress values.
+    // map = { "variables1": Complete, "from_str": None, ... }
+}
+
+fn count_collection_for(collection: &[HashMap<String, Progress>], value: Progress) -> usize {
+    let mut count = 0;
+    for map in collection {
+        for val in map.values() {
+            if val == &value {
+                count += 1;
+            }
+        }
+    }
+    count
+}
+
+fn count_collection_iterator(collection: &[HashMap<String, Progress>], value: Progress) -> usize {
+    // collection is a slice of hashmaps.
+    // collection = [{ "variables1": Complete, "from_str": None, ... },
+    //     { "variables2": Complete, ... }, ... ]
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn count_complete() {
+        let map = get_map();
+        assert_eq!(3, count_iterator(&map, Progress::Complete));
+    }
+
+    #[test]
+    fn count_equals_for() {
+        let map = get_map();
+        assert_eq!(
+            count_for(&map, Progress::Complete),
+            count_iterator(&map, Progress::Complete)
+        );
+    }
+
+    #[test]
+    fn count_collection_complete() {
+        let collection = get_vec_map();
+        assert_eq!(
+            6,
+            count_collection_iterator(&collection, Progress::Complete)
+        );
+    }
+
+    #[test]
+    fn count_collection_equals_for() {
+        let collection = get_vec_map();
+        assert_eq!(
+            count_collection_for(&collection, Progress::Complete),
+            count_collection_iterator(&collection, Progress::Complete)
+        );
+    }
+
+    fn get_map() -> HashMap<String, Progress> {
+        use Progress::*;
+
+        let mut map = HashMap::new();
+        map.insert(String::from("variables1"), Complete);
+        map.insert(String::from("functions1"), Complete);
+        map.insert(String::from("hashmap1"), Complete);
+        map.insert(String::from("arc1"), Some);
+        map.insert(String::from("as_ref_mut"), None);
+        map.insert(String::from("from_str"), None);
+
+        map
+    }
+
+    fn get_vec_map() -> Vec<HashMap<String, Progress>> {
+        use Progress::*;
+
+        let map = get_map();
+
+        let mut other = HashMap::new();
+        other.insert(String::from("variables2"), Complete);
+        other.insert(String::from("functions2"), Complete);
+        other.insert(String::from("if1"), Complete);
+        other.insert(String::from("from_into"), None);
+        other.insert(String::from("try_from_into"), None);
+
+        vec![map, other]
+    }
+}

exercises/standard_library_types/mod.rs

@@ -0,0 +1,7 @@
+mod arc1;
+mod box1;
+mod iterators1;
+mod iterators2;
+mod iterators3;
+mod iterators4;
+mod iterators5;

exercises/strings/README.md

@@ -1,9 +1,9 @@
-### Strings
+# Strings
 
 Rust has two string types, a string slice (`&str`) and an owned string (`String`).
 We're not going to dictate when you should use which one, but we'll show you how
 to identify and create them, as well as use them.
 
-#### Book Sections
+## Further information
 
 - [Strings](https://doc.rust-lang.org/book/ch08-02-strings.html)