Java 自定义栈结构

public class LinkedStack<T> {
	private static class Node<U> {
		U item;
		Node<U> next;
		Node() {item = null; next = null;}
		Node(U item, Node<U> next) {
			this.item = item;
			this.next = next;
		}
		
		boolean end() {
			return item == null && next == null;
		}
	}
	
	// top 是最顶上的节点
	private Node<T> top = new Node<T>();
	public void push(T item) {
		top = new Node<T>(item, top);
	}
	
	public T pop() {
		T result = top.item;
		if (!top.end()) {
			top = top.next;
		}
		return result;
	}
	
	public static void main(String[] args) {
		LinkedStack<String> lss = new LinkedStack<String>();
		for (String s : "my name is zhang zhao yu".split(" ")) {
			lss.push(s);
		}
		String s;
		while ((s = lss.pop()) != null) {
			System.out.println(s);
		}
	}

}