Fix borrow checker example (dangling reference)

3-borrow-checker/README.md

@@ -0,0 +1,27 @@
+# Borrow Checker example – fixed
+
+This small program demonstrates how Rust's borrow checker enforces lifetimes for references.
+
+The original version tried to return a reference (`&String`) that pointed to `name2`, a value that went out of scope at the end of an inner block. The compiler rightfully rejected the code because such a reference would have been dangling.
+
+The corrected version simply declares **both** strings in the same scope so that they live long enough for the returned reference to remain valid.
+
+Run it with:
+
+```bash
+cd 3-borrow-checker
+cargo run
+```
+
+You should see:
+
+```
+The bigger string is: Pranav
+```
+
+---
+
+Key take-aways:
+
+* A reference can never outlive the value it points to.
+* Keep referenced values in a scope that is at least as long as the references you hand out.

3-borrow-checker/src/main.rs

@@ -1,13 +1,14 @@
 fn main() {
+    // Move both names into the same scope so they live long enough
     let name1 = String::from("Pranav");
-    let bigger = {
-        let name2 = String::from("Tiago");
-        let bigger = bigger_string(&name1, &name2);
-        bigger;
-    };
-    println!("The bigger string is: {bigger}");
+    let name2 = String::from("Tiago");
+
+    let bigger = bigger_string(&name1, &name2);
+
+    println!("The bigger string is: {}", bigger);
 }
 
+// Returns a reference to the longer string slice
 fn bigger_string<'a>(a: &'a String, b: &'a String) -> &'a String {
     if a.len() > b.len() {
         a