Function main

publication/code/chapter01/use_refcell.rs:7–20

()

use std::rc::Rc;

fn main() {
    let shared_map: Rc<RefCell<_>> =
        Rc::new(RefCell::new(HashMap::new()));
    {
        let mut map: RefMut<_> = shared_map.borrow_mut();
        map.insert("kew", 1);
        map.insert("shieber", 2);
        map.insert("mon", 3);
        map.insert("hon", 4);
    }

    let total: i32 = shared_map.borrow().values().sum();
    println!("{}", total);
}