1 files changed, 46 insertions, 0 deletions
diff --git a/rustlings/exercises/09_strings/strings3.rs b/rustlings/exercises/09_strings/strings3.rs
new file mode 100644
index 0000000..f5e45b0
--- /dev/null
+++ b/rustlings/exercises/09_strings/strings3.rs
@@ -0,0 +1,46 @@
+fn trim_me(input: &str) -> &str {
+    // TODO: Remove whitespace from both ends of a string.
+}
+
+fn compose_me(input: &str) -> String {
+    // TODO: Add " world!" to the string! There are multiple ways to do this.
+}
+
+fn replace_me(input: &str) -> String {
+    // TODO: Replace "cars" in the string with "balloons".
+}
+
+fn main() {
+    // You can optionally experiment here.
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn trim_a_string() {
+        assert_eq!(trim_me("Hello!     "), "Hello!");
+        assert_eq!(trim_me("  What's up!"), "What's up!");
+        assert_eq!(trim_me("   Hola!  "), "Hola!");
+        assert_eq!(trim_me("Hi!"), "Hi!");
+    }
+
+    #[test]
+    fn compose_a_string() {
+        assert_eq!(compose_me("Hello"), "Hello world!");
+        assert_eq!(compose_me("Goodbye"), "Goodbye world!");
+    }
+
+    #[test]
+    fn replace_a_string() {
+        assert_eq!(
+            replace_me("I think cars are cool"),
+            "I think balloons are cool",
+        );
+        assert_eq!(
+            replace_me("I love to look at cars"),
+            "I love to look at balloons",
+        );
+    }
+}