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55 lines
1.2 KiB
55 lines
1.2 KiB
3 years ago
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use std::cell::RefCell;
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use std::rc::{Rc, Weak};
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#[derive(Debug)]
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struct Node {
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value: i32,
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parent: RefCell<Weak<Node>>,
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children: RefCell<Vec<Rc<Node>>>,
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}
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// ANCHOR: here
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fn main() {
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let leaf = Rc::new(Node {
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value: 3,
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parent: RefCell::new(Weak::new()),
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children: RefCell::new(vec![]),
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});
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println!(
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"leaf strong = {}, weak = {}",
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Rc::strong_count(&leaf),
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Rc::weak_count(&leaf),
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);
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{
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let branch = Rc::new(Node {
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value: 5,
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parent: RefCell::new(Weak::new()),
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children: RefCell::new(vec![Rc::clone(&leaf)]),
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});
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*leaf.parent.borrow_mut() = Rc::downgrade(&branch);
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println!(
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"branch strong = {}, weak = {}",
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Rc::strong_count(&branch),
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Rc::weak_count(&branch),
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);
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println!(
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"leaf strong = {}, weak = {}",
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Rc::strong_count(&leaf),
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Rc::weak_count(&leaf),
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);
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}
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println!("leaf parent = {:?}", leaf.parent.borrow().upgrade());
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println!(
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"leaf strong = {}, weak = {}",
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Rc::strong_count(&leaf),
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Rc::weak_count(&leaf),
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);
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}
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// ANCHOR_END: here
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