Class IntoIter

publication/code/chapter04/list_stack.rs:94–94

实现三种迭代功能

// 实现三种迭代功能
struct IntoIter<T: Clone>(LStack<T>);
impl<T: Clone> Iterator for IntoIter<T> {
    type Item = T;
    fn next(&mut self) -> Option<Self::Item> {