数组实现队列(一次性队列)

package com.dai.queue;

import java.util.Scanner;

public class ArrayQueueDemo {

    public static void main(String[] args) {
        //创建一个队列对象
        ArrayQueue arrayQueue = new ArrayQueue(3);
        char key = ' ';
        Scanner scanner = new Scanner(System.in);
        boolean loop = true;
        while(loop) {
            System.out.println("s(show):显示队列");
            System.out.println("e(exit):退出队列");
            System.out.println("a(append):添加数据到队列");
            System.out.println("g(get):从队列取出数据");
            System.out.println("h(head):查看队列头数据");
            key = scanner.next().charAt(0);
            switch (key) {
            case 's':
                arrayQueue.showQueue();
                break;
            case 'a':
                System.out.println("输入数字：");
                int value = scanner.nextInt();
                arrayQueue.addQueue(value);
                break;
            case 'g':
                try {
                    int res = arrayQueue.getQueue();
                    System.out.printf("取出的数据是%d
",res);
                }catch(Exception e) {
                    System.out.println(e.getMessage());
                }
                break;
            case 'h':
                try {
                    int res = arrayQueue.headQueue();
                    System.out.printf("队列头的数据是%d
",res);
                }catch(Exception e) {
                    System.out.println(e.getMessage());
                }
                break;
            case 'e':
                scanner.close();
                loop = false;
                break;
            default:
                break;
            }
            
        }
        System.out.println("程序退出");
    }

}
//使用数组模拟队列，编写一个ArrayQueue类
class ArrayQueue{
    private int maxSize;//队列最大容量
    private int front;//头
    private int rear;//尾
    private int[] arr; //存放数据
    
    public ArrayQueue(int arrMaxSize) {
        maxSize = arrMaxSize;
        arr = new int[maxSize];
        front = -1; //指向队列头部，的前一个位置
        rear = -1;//指向队列尾
    }
    //判断队列是否满
    public boolean isFull() {
        return rear == maxSize-1;
    }
    public boolean isEmpty() {
        return rear==front;
    }
    //添加数据带队列
    public void addQueue(int n) {
        //判断队列是否满
        if(isFull()) {
            System.out.println("队列已满，无法添加数据");
            return ;
        }
        rear ++; //rear后移
        arr[rear] = n;
    }
    //获取队列数据，出队
    public int getQueue() {
        if(isEmpty()) {
            throw new RuntimeException("对列空，不能取数据");
        }
        front ++;
        return arr[front];
    }
    //显示队列所有数据
    public void showQueue() {
        if(isEmpty()) {
            System.out.println("队列空，无数据");
            return;
        }
        int tmp = front;
        while(!isEmpty()) {
            System.out.printf("%d	",getQueue());
        }
        front = tmp;
    }
    //显示队列的头数据
    public int headQueue() {
        if(isEmpty()) {
            throw new RuntimeException("队列空，没有数据");
        }
        return arr[front+1];
    }
    
}