Example of an error when lifetime not specified

src/main.rs

@@ -0,0 +1,15 @@
+fn main() {
+    let s1 = "Hello worlc";
+    let s2 = "Hello";
+
+    let result: &str = longest(s1, s2);
+    println!("The longest string is {result}");
+}
+
+fn longest(a: &str, b: &str) -> &str {
+    if a.len() > b.len() {
+        a
+    } else {
+        b
+    }
+}