java---链表实现栈（简单实现）_demo demo = new node()

 栈--先进后出

所以压栈时我们采用头插法，这样一来头部指针便是栈顶。

出栈直接出头结点即可。

package com.Execise;
 
/**
 * @Author:XK
 * @Date: Created in 16:11 2022/1/16
 * @Description：
 **/
public class NodeStackDemo {
    private Node header;//栈顶
    private int elementCount;//元素个数
    private int size;//栈大小
    public NodeStackDemo(){
        header=null;
        elementCount=0;
        size=10;
    }
    public void push(int x){
        if(elementCount==10){
            System.out.println("stack is full!");
            return;
        }else if(elementCount==0){
            header=new Node();
            header.value=x;
            elementCount++;
        }else {
            Node node = new Node();
            node.value=x;
            node.next=header;
            header=node;
            elementCount++;
        }
    }
 
    public int pop(){
        if(elementCount==0){
            System.out.println("stack is empty!");
            return 0;
        }else{
            int i=header.value;
            header=header.next;
            elementCount--;
            return i;
        }
    }
 
    public static void main(String[] args) {
        NodeStackDemo nodeStackDemo = new NodeStackDemo();
        nodeStackDemo.push(1);
        nodeStackDemo.push(2);
        nodeStackDemo.push(3);
        nodeStackDemo.push(3);
        nodeStackDemo.push(3);
        System.out.println(nodeStackDemo.header);
        nodeStackDemo.pop();
        nodeStackDemo.pop();
        System.out.println(nodeStackDemo.header);
    }
 
}

3->3->3->2->1->null
3->2->1->null