lifetimes2 solution

exercises/16_lifetimes/lifetimes2.rs

@@ -1,6 +1,4 @@
-// So if the compiler is just validating the references passed to the annotated
-// parameters and the return type, what do we need to change?
-
+// Don't change this function.
 fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
     if x.len() > y.len() {
         x
@@ -10,11 +8,13 @@ fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
 }
 
 fn main() {
+    // TODO: Fix the compiler error by moving one line.
+
     let string1 = String::from("long string is long");
     let result;
     {
         let string2 = String::from("xyz");
-        result = longest(string1.as_str(), string2.as_str());
+        result = longest(&string1, &string2);
     }
-    println!("The longest string is '{}'", result);
+    println!("The longest string is '{result}'");
 }

solutions/16_lifetimes/lifetimes2.rs

@@ -1 +1,33 @@
-// Solutions will be available before the stable release. Thank you for testing the beta version 🥰
+fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
+    if x.len() > y.len() {
+        x
+    } else {
+        y
+    }
+}
+
+fn main() {
+    let string1 = String::from("long string is long");
+    // Solution1: You can move `strings2` out of the inner block so that it is
+    // not dropped before the print statement.
+    let string2 = String::from("xyz");
+    let result;
+    {
+        result = longest(&string1, &string2);
+    }
+    println!("The longest string is '{result}'");
+    // `string2` dropped at the end of the function.
+
+    // =========================================================================
+
+    let string1 = String::from("long string is long");
+    let result;
+    {
+        let string2 = String::from("xyz");
+        result = longest(&string1, &string2);
+        // Solution2: You can move the print statement into the inner block so
+        // that it is executed before `string2` is dropped.
+        println!("The longest string is '{result}'");
+        // `string2` dropped here (end of the inner scope).
+    }
+}