用数组实现栈

package datastructure;

import javax.xml.soap.Node;
import java.util.LinkedList;
import java.util.Scanner;

public class DoubleLinkedListDemo {
    public static void main(String[] args) {
        //测试一下 ArrayStack 是否正确
        //先创建一个 ArrayStack 对象->表示栈
        ArrayStack arrayStack = new ArrayStack(4);
        String key = "";
        boolean loop = true; //控制是否退出菜单
        Scanner scanner = new Scanner(System.in);
        System.out.println("show:表示显示栈");
        System.out.println("exit:退出程序");
        System.out.println("push:入栈");
        System.out.println("pop:出栈");
        while (loop){
            System.out.println("请输入你的选择");
            key = scanner.next();
            switch (key){
                case "show":
                    arrayStack.list();
                    break;
                case "push":
                    System.out.println("请输入一个数");
                    int value = scanner.nextInt();
                    arrayStack.push(value);
                    break;
                case "pop":
                    try {
                        int res = arrayStack.pop();
                        System.out.printf("出栈的是数据为%d\n",res);
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                    break;
                case "exit":
                    scanner.close();
                    loop = false;
                    break;
                default:
                    System.out.println("wrong instructions");
            }
        }
        System.out.println("程序退出了");
    }
}
//定义一个 ArrayStack 表示栈
class ArrayStack{
    private int maxSize;// 栈的大小
    private int[] stack; // 数组，数组模拟栈，数据就放在该数组
    private int top = -1;// top 表示栈顶，初始化为-1
    //构造器
    public ArrayStack(int maxSize){
        this.maxSize = maxSize;
        stack = new int[this.maxSize];
    }
    //栈满
    public boolean isFull(){
        return top == maxSize - 1;
    }
    //栈空
    public boolean isEmpty(){
        return top == -1;
    }
    //入栈-push
    public void push(int value){
        //先判断栈是否满
        if (isFull()){
            System.out.println("栈满");
            return;
        }
        top++;
        stack[top] = value;
    }
    //出栈-pop, 将栈顶的数据返回
    public int pop(){
        //先判断栈是否空
        if (isEmpty()){
            //抛出异常
            throw new RuntimeException("栈空");
        }
        int value = stack[top];
        top--;
        return value;
    }
    //显示栈的情况[遍历栈]， 遍历时，需要从栈顶开始显示数据
    public void list(){
        if (isEmpty()){
            System.out.println("栈空");
            return;
        }
        for (int i = top; i >= 0; i--) {
            System.out.printf("stack[%d]=%d\n",i,stack[i]);
        }
    }
}