Update Exercises Directory Names to Reflect Order

exercises/05_vecs/vecs2.rs

@@ -0,0 +1,50 @@
+// vecs2.rs
+//
+// A Vec of even numbers is given. Your task is to complete the loop so that
+// each number in the Vec is multiplied by 2.
+//
+// Make me pass the test!
+//
+// Execute `rustlings hint vecs2` or use the `hint` watch subcommand for a hint.
+
+// I AM NOT DONE
+
+fn vec_loop(mut v: Vec<i32>) -> Vec<i32> {
+    for element in v.iter_mut() {
+        // TODO: Fill this up so that each element in the Vec `v` is
+        // multiplied by 2.
+        ???
+    }
+
+    // At this point, `v` should be equal to [4, 8, 12, 16, 20].
+    v
+}
+
+fn vec_map(v: &Vec<i32>) -> Vec<i32> {
+    v.iter().map(|element| {
+        // TODO: Do the same thing as above - but instead of mutating the
+        // Vec, you can just return the new number!
+        ???
+    }).collect()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_vec_loop() {
+        let v: Vec<i32> = (1..).filter(|x| x % 2 == 0).take(5).collect();
+        let ans = vec_loop(v.clone());
+
+        assert_eq!(ans, v.iter().map(|x| x * 2).collect::<Vec<i32>>());
+    }
+
+    #[test]
+    fn test_vec_map() {
+        let v: Vec<i32> = (1..).filter(|x| x % 2 == 0).take(5).collect();
+        let ans = vec_map(&v);
+
+        assert_eq!(ans, v.iter().map(|x| x * 2).collect::<Vec<i32>>());
+    }
+}