介绍

视频地址：www.bilibili.com/video/av78062009/
相关源码：github.com/anonymousGiga/Rust-link...

详细内容

在上一节我们定义了我们的双链表，本节我们来给双链表创建new函数和pushfront函数。

new

impl<T> Node<T> {
    fn new(elem: T) -> Rc<RefCell<Self>> {
        Rc::new(RefCell::new(Node {
            elem: elem,
            prev: None,
            next: None,
        }))
    }
}

impl<T> List<T> {
    pub fn new() -> Self {
        List { head: None, tail: None }
    }
}

push_front

下面我们增加添加元素的函数，如下：

    pub fn push_front(&mut self, elem: T) {
        let node = Node::new(elem);
        match self.head.take() {
            Some(head) => {
                head.borrow_mut().prev = Some(node.clone());
                node.borrow_mut().next = Some(head);
                self.head = Some(node);
            }
            None => {
                self.tail = Some(node.clone());
                self.head = Some(node);
            }
        }
    }

完整代码

添加后的完整代码如下：

use std::rc::Rc;
use std::cell::RefCell;

pub struct List<T> {
    head: Link<T>,
    tail: Link<T>,
}

type Link<T> = Option<Rc<RefCell<Node<T>>>>;

struct Node<T> {
    elem: T,
    next: Link<T>,
    prev: Link<T>,
}

impl<T> Node<T> {
    fn new(elem: T) -> Rc<RefCell<Self>> {
        Rc::new(RefCell::new(Node {
            elem: elem,
            prev: None,
            next: None,
        }))
    }
}

impl<T> List<T> {
    pub fn new() -> Self {
        List { head: None, tail: None }
    }

    pub fn push_front(&mut self, elem: T) {
        let node = Node::new(elem);
        match self.head.take() {
            Some(head) => {
                head.borrow_mut().prev = Some(node.clone());

                node.borrow_mut().next = Some(head);
                self.head = Some(node);
            }

            None => {
                self.tail = Some(node.clone());
                self.head = Some(node);
            }
        }
    }
}

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