3 files changed, 65 insertions, 6 deletions
diff --git a/rustlings/solutions/16_lifetimes/lifetimes1.rs b/rustlings/solutions/16_lifetimes/lifetimes1.rs
index dcf2377..4f56834 100644
--- a/rustlings/solutions/16_lifetimes/lifetimes1.rs
+++ b/rustlings/solutions/16_lifetimes/lifetimes1.rs
@@ -1,4 +1,24 @@
+// The Rust compiler needs to know how to check whether supplied references are
+// valid, so that it can let the programmer know if a reference is at risk of
+// going out of scope before it is used. Remember, references are borrows and do
+// not own their own data. What if their owner goes out of scope?
+
+fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
+    //    ^^^^     ^^          ^^          ^^
+    if x.len() > y.len() { x } else { y }
+}
+
 fn main() {
-    // DON'T EDIT THIS SOLUTION FILE!
-    // It will be automatically filled after you finish the exercise.
+    // You can optionally experiment here.
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_longest() {
+        assert_eq!(longest("abcd", "123"), "abcd");
+        assert_eq!(longest("abc", "1234"), "1234");
+    }
 }
diff --git a/rustlings/solutions/16_lifetimes/lifetimes2.rs b/rustlings/solutions/16_lifetimes/lifetimes2.rs
index dcf2377..3ca4909 100644
--- a/rustlings/solutions/16_lifetimes/lifetimes2.rs
+++ b/rustlings/solutions/16_lifetimes/lifetimes2.rs
@@ -1,4 +1,29 @@
+fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
+    if x.len() > y.len() { x } else { y }
+}
+
 fn main() {
-    // DON'T EDIT THIS SOLUTION FILE!
-    // It will be automatically filled after you finish the exercise.
+    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).
+    }
 }
diff --git a/rustlings/solutions/16_lifetimes/lifetimes3.rs b/rustlings/solutions/16_lifetimes/lifetimes3.rs
index dcf2377..16a5a68 100644
--- a/rustlings/solutions/16_lifetimes/lifetimes3.rs
+++ b/rustlings/solutions/16_lifetimes/lifetimes3.rs
@@ -1,4 +1,18 @@
+// Lifetimes are also needed when structs hold references.
+
+struct Book<'a> {
+    //     ^^^^ added a lifetime annotation
+    author: &'a str,
+    //       ^^
+    title: &'a str,
+    //      ^^
+}
+
 fn main() {
-    // DON'T EDIT THIS SOLUTION FILE!
-    // It will be automatically filled after you finish the exercise.
+    let book = Book {
+        author: "George Orwell",
+        title: "1984",
+    };
+
+    println!("{} by {}", book.title, book.author);
 }