Complete vectors exercise

exercises/05_vecs/vecs1.rs

@@ -7,12 +7,12 @@
 //
 // Execute `rustlings hint vecs1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
 
 fn array_and_vec() -> ([i32; 4], Vec<i32>) {
     let a = [10, 20, 30, 40]; // a plain array
-    let v = // TODO: declare your vector here with the macro for vectors
 
+    // this is the common way to do it using the vector macro
+    let v = vec![10, 20, 30, 40];// TODO: declare your vector here with the macro for vectors
     (a, v)
 }
 

exercises/05_vecs/vecs2.rs

@@ -7,13 +7,14 @@
 //
 // 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.
-        ???
+        
+        *element *= 2;
+        // the star in front of the element is a dereference operator
+        // it is used to access the value of the element to change it.
     }
 
     // At this point, `v` should be equal to [4, 8, 12, 16, 20].
@@ -24,7 +25,7 @@ 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!
-        ???
+        element * 2
     }).collect()
 }