#![allow(unused_variables)]
use std::rc::Rc;
use std::rc::Weak;
use std::cell::RefCell;
struct Owner {
    name: String,
    gadgets: RefCell<Vec<Weak<Gadget>>>,
}
struct Gadget {
    id: i32,
    owner: Rc<Owner>,
}
fn main() {
    let gadget_owner: Rc<Owner> = Rc::new(Owner {
        name: "Gadget Man".to_string(),
        gadgets: RefCell::new(vec![]),
    });
    let gadget1 = Rc::new(Gadget {
        id: 1,
        owner: Rc::clone(&gadget_owner),
    });
    let gadget2 = Rc::new(Gadget {
        id: 2,
        owner: Rc::clone(&gadget_owner),
    });
    {
        let mut gadgets = gadget_owner.gadgets.borrow_mut();
        gadgets.push(Rc::downgrade(&gadget1));
        gadgets.push(Rc::downgrade(&gadget2));
    }
    for gadget_weak in gadget_owner.gadgets.borrow().iter() {
        let gadget = gadget_weak.upgrade().unwrap();
        println!("Gadget {} owned by {}", gadget.id, gadget.owner.name);
    }
}