lifetimes3 solution

solutions/16_lifetimes/lifetimes3.rs

@@ -1 +1,18 @@
-// Solutions will be available before the stable release. Thank you for testing the beta version 🥰
+// Lifetimes are also needed when structs hold references.
+
+struct Book<'a> {
+    //     ^^^^ added a lifetime annotation
+    author: &'a str,
+    //       ^^
+    title: &'a str,
+    //      ^^
+}
+
+fn main() {
+    let book = Book {
+        author: "George Orwell",
+        title: "1984",
+    };
+
+    println!("{} by {}", book.title, book.author);
+}