智能指针

Box

fn main() {
    let num = Box::new(100); // 存放在堆上
}

fn main() {
    let name = Box::new(String::from("Tom"));
    let name2 = *name;  // Value moved here
    println!("name2: {}!", name2);
    // println!("name: {}", name);  // 会报错，name丢失所有权
}

RefCell

fn main() {
    // name不可变
    let name = RefCell::new(String::from("Tom"));

    // 这里在修改name
    name.borrow_mut().push_str("666");

    println!("name: {}", name.borrow());  // name: Tom666
}

Rc