add solutions for ownership.md

solutions/ownership/ownership.md

@@ -0,0 +1,151 @@
+1.
+```rust
+fn main() {
+    let x = String::from("hello, world");
+    let y = x.clone();
+    println!("{},{}",x,y);
+}
+```
+
+```rust
+fn main() {
+    let x = "hello, world";
+    let y = x;
+    println!("{},{}",x,y);
+}
+```
+
+```rust
+fn main() {
+    let x = &String::from("hello, world");
+    let y = x;
+    println!("{},{}",x,y);
+}
+```
+
+```rust
+fn main() {
+    let x = 10;
+    let y = x;
+    println!("{},{}",x,y);
+}
+```
+
+2.
+```rust
+// Don't modify code in main!
+fn main() {
+    let s1 = String::from("hello, world");
+    let s2 = take_ownership(s1);
+
+    println!("{}", s2);
+}
+
+// Only modify the code below!
+fn take_ownership(s: String) -> String {
+    println!("{}", s);
+    s
+}
+```
+
+3.
+```rust
+fn main() {
+    let s = give_ownership();
+    println!("{}", s);
+}
+
+// Only modify the code below!
+fn give_ownership() -> String {
+    let s = String::from("hello, world");
+    // convert String to Vec
+    let _s = s.as_bytes();
+    s
+}
+```
+
+```rust
+fn main() {
+    let s = give_ownership();
+    println!("{}", s);
+}
+
+// Only modify the code below!
+fn give_ownership() -> String {
+    let s = String::from("hello, world");
+    s
+}
+```
+
+4.
+```rust
+fn main() {
+    let s = String::from("hello, world");
+
+    print_str(s.clone());
+
+    println!("{}", s);
+}
+
+fn print_str(s: String)  {
+    println!("{}",s)
+}
+```
+
+5.
+```rust
+fn main() {
+    let x = (1, 2, (), "hello");
+    let y = x;
+    println!("{:?}, {:?}", x, y);
+}
+```
+
+6.
+```rust
+fn main() {
+    let s = String::from("hello, ");
+    
+    // modify this line only !
+    let mut s1 = s;
+
+    s1.push_str("world")
+}
+```
+
+7.
+```rust
+fn main() {
+    let x = Box::new(5);
+    
+    let mut y = Box::new(3);       // implement this line, dont change other lines!
+    
+    *y = 4;
+    
+    assert_eq!(*x, 5);
+}
+```
+
+8.
+```rust
+fn main() {
+    let t = (String::from("hello"), String::from("world"));
+ 
+    let _s = t.0;
+ 
+    // modify this line only, don't use `_s`
+    println!("{:?}", t.1);
+ }
+```
+
+9.
+```rust
+fn main() {
+    let t = (String::from("hello"), String::from("world"));
+
+    // fill the blanks
+    let (s1, s2) = t.clone();
+
+    println!("{:?}, {:?}, {:?}", s1, s2, t); // -> "hello", "world", ("hello", "world")
+}
+```