007 通過連結串列學Rust之支援泛型

視訊地址：www.bilibili.com/video/av78062009/
相關原始碼：github.com/anonymousGiga/Rust-link...

本節我們讓我們的連結串列支援泛型。首先修改我們的定義如下：

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

type Link<T> = Option<Box<Node<T>>>;

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

整體的實現程式碼如下：

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

type Link<T> = Option<Box<Node<T>>>;

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

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

    pub fn push(&mut self, elem: T) {
        let node = Box::new(Node {
            elem: elem,
            next: self.head.take(),
        });
        self.head = Some(node);
    }

    pub fn pop(&mut self) -> Option<T> {
        self.head.take().map(|node| {
            self.head = node.next;
            node.elem
        })
    }
}

impl<T> Drop for List<T> {
    fn drop(&mut self) {
        let mut link = self.head.take();
        while let Some(mut node) = link {
            link = node.next.take();
        }
    }
}

#[cfg(test)]
mod tests {
    use super::List;

    #[test]
    fn basics() {
        let mut list = List::new();
        assert_eq!(list.pop(), None);

        list.push(1);
        list.push(2);
        list.push(3);

        assert_eq!(list.pop(), Some(3));
        assert_eq!(list.pop(), Some(2));

        list.push(4);
        list.push(5);

        assert_eq!(list.pop(), Some(5));
        assert_eq!(list.pop(), Some(4));

        assert_eq!(list.pop(), Some(1));
        assert_eq!(list.pop(), None);
    }
}

本作品採用《CC 協議》，轉載必須註明作者和本文連結