rust-book/reference_counting/src/main.rs

29 lines
628 B
Rust

#[derive(Debug)]
enum List {
Cons(Rc<RefCell<i32>>, Rc<List>),
Nil,
}
use List::{Cons, Nil};
use std::rc::Rc;
use std::cell::RefCell;
fn main() {
let value = Rc::new(RefCell::new(5));
let a = Rc::new(Cons(Rc::clone(&value), Rc::new(Nil)));
println!("a before = {:?}", a);
let b = Cons(Rc::new(RefCell::new(6)), Rc::clone(&a));
println!("b before = {:?}", b);
let c = Cons(Rc::new(RefCell::new(10)), Rc::clone(&a));
println!("c before = {:?}", a);
*value.borrow_mut() += 10;
println!("a after = {:?}", a);
println!("b after = {:?}", b);
println!("c after = {:?}", c);
}