package com.rao.linkList;

/**

 * @author Srao

 * @className LinkedStack

 * @date 2019/12/3 13:59

 * @package com.rao.linkList

 * @Description 基于链表的栈

 */

public class LinkedStack {

    /**

     * 定义节点

     */

    static class Node{

        private String data;

        private Node next;

        public Node(String data) {

            this.data = data;

            this.next = null;

        }

        public String getData() {

            return data;

        }

    }

    //栈顶元素

    private Node top;

    /**

     * 入栈

     * @param s

     */

    public void push(String s){

        Node node = new Node(s);

        if (top == null){

            top = node;

        }else {

            node.next = top;

            top = node;

        }

    }

    /**

     * 出栈

     * @return

     */

    public Node pop(){

        Node node = null;

        if (top.next != null){

            node = top;

            top = top.next;

        }else {

            node = top;

            top = null;

        }

        return node;

    }

    public static void main(String[] args) {

        LinkedStack linkedStack = new LinkedStack();

        linkedStack.push("aa");

        linkedStack.push("11");

        linkedStack.push("@@");

        System.out.println(linkedStack.top.getData());

        System.out.println(linkedStack.pop().getData());

        System.out.println(linkedStack.pop().getData());

        System.out.println(linkedStack.pop().getData());

    }

}