move_semantics done

exercises/move_semantics/move_semantics4.rs

@@ -4,12 +4,35 @@
 // freshly created vector from fill_vec to its caller.
 // Execute `rustlings hint move_semantics4` for hints!
 
-// I AM NOT DONE
+// // original code
+// fn main() {
+//     let vec0 = Vec::new();
 
+//     let mut vec1 = fill_vec(vec0);
+
+//     println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
+
+//     vec1.push(88);
+
+//     println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
+// }
+
+// // original code (cont'd)
+// // `fill_vec()` no longer takes `vec: Vec<i32>` as argument
+// fn fill_vec() -> Vec<i32> {
+//     let mut vec = vec;
+
+//     vec.push(22);
+//     vec.push(44);
+//     vec.push(66);
+
+//     vec
+// }
+// // end of original code
+
+// solution
 fn main() {
-    let vec0 = Vec::new();
-
-    let mut vec1 = fill_vec(vec0);
+    let mut vec1 = fill_vec();
 
     println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
 
@@ -18,9 +41,11 @@ fn main() {
     println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
 }
 
+// solution (cont'd)
 // `fill_vec()` no longer takes `vec: Vec<i32>` as argument
 fn fill_vec() -> Vec<i32> {
-    let mut vec = vec;
+    // create mutable vec
+    let mut vec = Vec::new();
 
     vec.push(22);
     vec.push(44);
@@ -28,3 +53,4 @@ fn fill_vec() -> Vec<i32> {
 
     vec
 }
+// end of solution

exercises/move_semantics/move_semantics5.rs

@@ -3,13 +3,23 @@
 // adding, changing or removing any of them.
 // Execute `rustlings hint move_semantics5` for hints :)
 
-// I AM NOT DONE
+// // original code
+// fn main() {
+//     let mut x = 100;
+//     let y = &mut x;
+//     let z = &mut x;
+//     *y += 100;
+//     *z += 1000;
+//     assert_eq!(x, 1200);
+// }
+// // end of orignal code
 
+// solution
 fn main() {
     let mut x = 100;
     let y = &mut x;
-    let z = &mut x;
     *y += 100;
+    let z = &mut x;
     *z += 1000;
     assert_eq!(x, 1200);
 }

exercises/move_semantics/move_semantics6.rs

@@ -2,24 +2,55 @@
 // Make me compile! `rustlings hint move_semantics6` for hints
 // You can't change anything except adding or removing references
 
-// I AM NOT DONE
+// // original code
+// fn main() {
+//     let data = "Rust is great!".to_string();
 
+//     get_char(data);
+
+//     string_uppercase(&data);
+// }
+
+// // original code (cont'd)
+// // Should not take ownership
+// fn get_char(data: String) -> char {
+//     data.chars().last().unwrap()
+// }
+
+// // original code (cont'd)
+// // Should take ownership
+// fn string_uppercase(mut data: &String) {
+//     data = &data.to_uppercase();
+
+//     println!("{}", data);
+// }
+// // end of original code
+
+// solution
 fn main() {
     let data = "Rust is great!".to_string();
 
-    get_char(data);
+    // change passed data to ref so as to not take ownership of `data`
+    get_char(&data);
 
-    string_uppercase(&data);
+    // remove ref so string_uppercase takes ownership of `data`
+    string_uppercase(data);
 }
 
+// solution (cont'd)
 // Should not take ownership
-fn get_char(data: String) -> char {
+// add ref to argument type
+fn get_char(data: &String) -> char {
     data.chars().last().unwrap()
 }
 
+// solution (cont'd)
 // Should take ownership
-fn string_uppercase(mut data: &String) {
-    data = &data.to_uppercase();
+// remove ref from argument type
+fn string_uppercase(mut data: String) {
+    // remove ref from data
+    data = data.to_uppercase();
 
     println!("{}", data);
 }
+// end of solution