ex(05): vecs

.rustlings-state.txt

···
 DON'T EDIT THIS FILE!
 
-vecs1
+move_semantics1
 
 intro1
 intro2
···
 primitive_types3
 primitive_types4
 primitive_types5
-primitive_types6
+primitive_types6
+vecs1
+vecs2

exercises/05_vecs/vecs1.rs

···
     // TODO: Create a vector called `v` which contains the exact same elements as in the array `a`.
     // Use the vector macro.
     // let v = ???;
+    let v = vec![10, 20, 30, 40];
 
     (a, v)
 }

exercises/05_vecs/vecs2.rs

···
     for element in input {
         // TODO: Multiply each element in the `input` slice by 2 and push it to
         // the `output` vector.
+        output.push(element * 2)
     }
 
     output
···
         .iter()
         .map(|element| {
             // ???
+            element * 2
         })
         .collect()
 }

solutions/05_vecs/vecs1.rs

···
+fn array_and_vec() -> ([i32; 4], Vec<i32>) {
+    let a = [10, 20, 30, 40]; // Array
+
+    // Used the `vec!` macro.
+    let v = vec![10, 20, 30, 40];
+
+    (a, v)
+}
+
 fn main() {
-    // DON'T EDIT THIS SOLUTION FILE!
-    // It will be automatically filled after you finish the exercise.
+    // You can optionally experiment here.
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_array_and_vec_similarity() {
+        let (a, v) = array_and_vec();
+        assert_eq!(a, *v);
+    }
 }

solutions/05_vecs/vecs2.rs

···
+fn vec_loop(input: &[i32]) -> Vec<i32> {
+    let mut output = Vec::new();
+
+    for element in input {
+        output.push(2 * element);
+    }
+
+    output
+}
+
+fn vec_map_example(input: &[i32]) -> Vec<i32> {
+    // An example of collecting a vector after mapping.
+    // We map each element of the `input` slice to its value plus 1.
+    // If the input is `[1, 2, 3]`, the output is `[2, 3, 4]`.
+    input.iter().map(|element| element + 1).collect()
+}
+
+fn vec_map(input: &[i32]) -> Vec<i32> {
+    // We will dive deeper into iterators, but for now, this is all what you
+    // had to do!
+    // Advanced note: This method is more efficient because it automatically
+    // preallocates enough capacity. This can be done manually in `vec_loop`
+    // using `Vec::with_capacity(input.len())` instead of `Vec::new()`.
+    input.iter().map(|element| 2 * element).collect()
+}
+
 fn main() {
-    // DON'T EDIT THIS SOLUTION FILE!
-    // It will be automatically filled after you finish the exercise.
+    // You can optionally experiment here.
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_vec_loop() {
+        let input = [2, 4, 6, 8, 10];
+        let ans = vec_loop(&input);
+        assert_eq!(ans, [4, 8, 12, 16, 20]);
+    }
+
+    #[test]
+    fn test_vec_map_example() {
+        let input = [1, 2, 3];
+        let ans = vec_map_example(&input);
+        assert_eq!(ans, [2, 3, 4]);
+    }
+
+    #[test]
+    fn test_vec_map() {
+        let input = [2, 4, 6, 8, 10];
+        let ans = vec_map(&input);
+        assert_eq!(ans, [4, 8, 12, 16, 20]);
+    }
 }