package com.my;

/**

 * 链式栈

 * @author wanjn

 *

 */

public class LinkedStack {

        private Node head;

        private int size;

        //入栈，前插入构造链表，删除头结点实现栈；向后插入构造链表，删除头结点实现队列

        public void push(Object value){

            if (head ==null) {

                head = new Node(null, value);

            }else {

                head = new Node(head, value);

            }

        }

        //出栈

        public Object pop(){

            Object oldValue =null;

            if (head!=null) {

                oldValue = head.value;

                head = head.next;

            }

            return oldValue;

        }

        @Override

        public String toString() {

            Node temp = head;

            String result= "";

            while (temp!=null) {

                result +=temp.value+" ,";

                temp = temp.next;

            }

            return result;

        }

        private class Node{

            Node next;

            Object value;

            Node(Node next,Object value){

                this.next = next;

                this.value = value;

            }

        }

}