Documentation
/**
    # 简单链表

    ```
    use rt_lists::third::List;
    ```

    ## 方法

    - List::new()
    - List::push()
    - List::pop()
    - List::peek()
    - List::peek_mut()

    ## 迭代器
    
    - into_iter()
    - iter()
    - iter_mut()

    ## example

    ```rust
    use rt_lists::third::List;
    let mut list = List::new();
    list.push(1);
    list.push(2);
    assert_eq!(list.pop(), Some(2));
    ```

 */

pub mod first;
pub mod second;
pub mod third;

pub fn add(left: u64, right: u64) -> u64 {
    left + right
}

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

    #[test]
    fn it_works() {
        let result = add(2, 2);
        assert_eq!(result, 4);
    }
}