Stack(栈)

ゝ一纸荒年。 2021-08-11 22:10 417阅读 0赞

【一】Stack(栈)

> 特点：它是一个先进后出的有序列表  
>     允许插入和删除的一端为栈顶(top)，另一端为栈底(bottom)  
>     出栈pop,入栈push  
> 数组模拟栈  
> 1.判断栈是否为空  
> 2.判断栈是否已满  
> 3.入栈  
> 4.出栈

【二】代码实现

import java.util.Scanner;
    public class StactTest2 {
    	public static void main(String[] args) {
    		Stack stack=new Stack(10);
    		Scanner sc=new Scanner(System.in);
    		boolean loop=true;
    		String key="";
    		System.out.println("show:表示遍历栈");
    		System.out.println("exit:表示退出程序");
    		System.out.println("pop:表示出栈");
    		System.out.println("push:表示入栈");
    		while(loop) {
    			key=sc.next();
    			switch(key) {
    			case "show":
    				stack.listStack();
    				break;
    			case "exit":
    				sc.close();
    				loop=false;
    				break;
    			case "pop":
    				try {
    					int num=stack.pop();
    					System.out.println(num);
    				}catch(Exception e){
    					System.out.println(e.getMessage());
    				}
    				break;
    			case "push":
    				System.out.println("请输入一个整数：");
    				int num=sc.nextInt();
    				stack.push(num);
    				break;
    			default:
    				System.out.println("输入命令异常");
    				break;
    			}
    		}
    		
    	}
    }
    
    class Stack{
    	private int maxSize;
    	private int[] arr;
    	private int top=-1;
    	
    	//初始化
    	Stack(int maxSize){
    		this.maxSize=maxSize;
    		arr=new int[maxSize];
    	}
    	
    	//判断栈是否为空
    	public boolean isEmpty() {
    		return top==-1;
    	}
    	
    	//判断栈是否已满
    	public boolean isFull() {
    		return top>maxSize-1;
    	}
    	
    	//入栈
    	public void push(int num) {
    		if(isFull()) {
    			System.out.println("栈满~");
    			return;
    		}
    		top++;
    		arr[top]=num;
    	}
    	
    	//出栈
    	public int pop() {
    		if(isEmpty()) {
    			throw new RuntimeException("栈为空");
    		}
    		int num=arr[top];
    		top--;
    		return num;
    	}
    	
    	//显示栈即遍历栈
    	public void listStack() {
    		if(isEmpty()) {
    			System.out.println("栈为空");
    			return ;
    		}
    		for(int i=top;i>=0;i--) {
    			System.out.print(arr[i]+"   ");
    		}
    	}
    }

【三】输出截图

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1RoZV9CZXN0X0hhY2tlcg_size_16_color_FFFFFF_t_70][]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1RoZV9CZXN0X0hhY2tlcg_size_16_color_FFFFFF_t_70]: /images/20210811/7bee8f84c98d4657a4e696bddef6e084.png