java 队列的实现

public static void main(String args[]) throws IOException {

        ArrayQueue arrayQueue = new ArrayQueue(3);
        char key=' ';//接收用户输入
        Scanner scan= new Scanner(System.in);
        boolean loop=true;
        while (loop){
            System.out.println("s:显示队列");
            System.out.println("e:退出程序");
            System.out.println("a:添加数据到队列");
            System.out.println("g:队列里取数据");
            System.out.println("h:显示头");
            System.out.println("r:显示尾");
            key = scan.next().charAt(0);
            switch (key){
                case 's':
                    try {
                    arrayQueue.showQueue();
                        System.out.println("已显示全部数据");
                    }catch (Exception e) {
                        System.out.println(e.getMessage());
                    }
                    break;
                case  'a':
                    try {
                    System.out.println("请输入一个数据");
                    int val=scan.nextInt();
                    arrayQueue.addQueue(val);
                        System.out.println("已成功添加数据");
                    }catch (Exception e) {
                        System.out.println(e.getMessage());
                    }
                    break;
                case 'g':
                    try {
                    int res=arrayQueue.getQueue();
                    System.out.printf("%d\n",res);
                    }catch (Exception e) {
                        System.out.println(e.getMessage());
                    }
                    break;
                case 'h' :
                    try{
                    int res=arrayQueue.headQueue();
                    System.out.printf("取出的数据是:%d\n",res);
                    }catch (Exception e) {
                        System.out.println(e.getMessage());
                    }
                    break;
                case 'r':
                    try{
                      int res=  arrayQueue.rearQueue();
                      System.out.printf("取出的数据是:%d\n",res);
                    }catch (Exception e) {
                        System.out.println(e.getMessage());
                    }
                    break;
                case 'e':
                    scan.close();
                    loop=false;
                    break;
                default:
                    break;

            }
        }
        System.out.println("程序退出");
    }

class ArrayQueue{
    //属性
    private int maxSize;//最大容器
    private int front;//队列头
    private int rear;//队列尾
    private int[] arr;//用于存放数据,模拟队列

    //创建队列的构造器
    public ArrayQueue(int arrMaxSize) {
        maxSize = arrMaxSize;
        arr=new int[arrMaxSize];
        front = rear =0;
    }
    //判断队列空
    public boolean isEmpty() {
       return front ==rear;
    }
    //判断队列满的
    public boolean isFull() {
        if(rear!=front)
        return (rear-front)%maxSize==0;
        return false;
    }
    //添加数据
    public void addQueue(int n){
        //判断队列是否满
        if(isFull())throw new RuntimeException("队列满不能添加数据");
        int val=rear;
        rear++;
        arr[val%maxSize]=n;
    }
    //取数据
    public int getQueue(){
        if(isEmpty())throw new RuntimeException("没有数据!");
        int val =front;
        front++;
        return arr[val%maxSize];
    }
    //显示所有数据
    public void showQueue(){
        if(isEmpty()){
            throw new RuntimeException("队列为空!");
        }
        for(int i=front;i<rear; i++){
            System.out.printf("arr[%d]=%d\n",i%maxSize,arr[i%maxSize]);
        }
    }
    //显示头数据
    public int headQueue(){
        if (isEmpty()) {
            throw new RuntimeException("没有数据");
        }
        return arr[front%maxSize];
    }
    //显示尾数据
    public int rearQueue(){
        if (isEmpty()) {
            throw new RuntimeException("没数据");
        }
        return arr[(rear-1)%maxSize];
    }


}

来源：CSDN

作者：fylive

链接：https://blog.csdn.net/qq_39472229/article/details/103827398