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45f869902b
Fix minor grammatical errors in Day 1: Morning. Speaker notes 6.5: "the `-> ()` return type" changed to "the return type". The compiler will infer the unit type for any type omitted.
40 lines
1.1 KiB
Markdown
40 lines
1.1 KiB
Markdown
---
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minutes: 3
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---
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# Functions
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<!-- mdbook-xgettext: skip -->
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```rust,editable
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fn gcd(a: u32, b: u32) -> u32 {
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if b > 0 {
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gcd(b, a % b)
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} else {
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a
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}
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}
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fn main() {
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println!("gcd: {}", gcd(143, 52));
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}
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```
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<details>
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- Declaration parameters are followed by a type (the reverse of some programming
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languages), then a return type.
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- The last expression in a function body (or any block) becomes the return
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value. Simply omit the `;` at the end of the expression. The `return` keyword
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can be used for early return, but the "bare value" form is idiomatic at the
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end of a function (refactor `gcd` to use a `return`).
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- Some functions have no return value, and return the 'unit type', `()`. The
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compiler will infer this if the return type is omitted.
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- Overloading is not supported -- each function has a single implementation.
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- Always takes a fixed number of parameters. Default arguments are not
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supported. Macros can be used to support variadic functions.
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- Always takes a single set of parameter types. These types can be generic,
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which will be covered later.
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</details>
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