1 files changed, 48 insertions, 1 deletions
diff --git a/solutions/09_strings/strings3.rs b/solutions/09_strings/strings3.rs
index 4e18198..a478e62 100644
--- a/solutions/09_strings/strings3.rs
+++ b/solutions/09_strings/strings3.rs
@@ -1 +1,48 @@
-// Solutions will be available before the stable release. Thank you for testing the beta version 🥰
+fn trim_me(input: &str) -> &str {
+    input.trim()
+}
+
+fn compose_me(input: &str) -> String {
+    // The macro `format!` has the same syntax as `println!`, but it returns a
+    // string instead of printing it to the terminal.
+    // Equivalent to `input.to_string() + " world!"`
+    format!("{input} world!")
+}
+
+fn replace_me(input: &str) -> String {
+    input.replace("cars", "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!");
+    }
+
+    #[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",
+        );
+    }
+}