Understanding Ownership

ownership.rs

fn main() {
    let x: i32 = 2;
    take_ownership_x(x);
    println!("x = {}", x);

    let y = String::from("Hello");
    take_ownership(y);
    // the following line shall fail since value borrowed above
    // println!("y = {}", y);

    let o = String::from("Hello");
    println!("o len = {}", get_len(&o));
    println!("o = {}", o);
    
    let z = String::from("Hello");
    take_ownership(z.clone());
    println!("z = {}", z);

    // Mutable References
    let mut g = String::from("Hello");
    g = take_ownership_and_give(g);
    println!("g = {}", g);

    // Mutable References
    let mut k = String::from("Hello");
    take_ownership_and_update(&mut k);
    println!("k = {}", k);
}

fn take_ownership_x(x: i32) {
    println!("x = {}", x)
}

fn take_ownership(y: String) {
    println!("y = {}", y)
}

fn take_ownership_and_give(mut y: String) -> String {
    y.push_str(" World");
    y
}

fn take_ownership_and_update(y: &mut String) {
    y.push_str(" World")
}

fn get_len(y: &String) -> usize {
    y.len()
}

reference https://doc.rust-lang.org/book/ch04-00-understanding-ownership.html#understanding-ownership

playground https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=6a0c3a11f56ffc61e600049989da9e82