Method print_node

code/chapter08/dfs.rs:44–51

(&self)

    }

    fn print_node(&self) {
        let mut curr = self.first.clone();
        while let Some(val) = curr {
            print!("[{}]", &val.borrow().data);
            curr = val.borrow().next.clone();
        }
        print!("\n");
    }

    fn insert(&mut self, data: usize) {
        let node = Rc::new(RefCell::new(Node::new(data)));