public class Queue {
    private int maxSzie; //隊(duì)列中能存儲(chǔ)的最大個(gè)數(shù)
    private int frontPoint; //頭指針指向隊(duì)頭
    private int rearPoint; //尾指針指向隊(duì)尾的后一個(gè)數(shù)據(jù)
    private int[] array; //模擬隊(duì)列的數(shù)組

    /**
     * 初始化隊(duì)列
     */
    public Queue(int max) {
        maxSzie = max;
        frontPoint = 0;
        rearPoint = 0;
        array = new int[max];
    }

    /**
     * 判斷隊(duì)列是否為空
     */
    public boolean isEmpty(){
        return frontPoint == rearPoint;
    }
    /**
     * 判斷隊(duì)列是否已滿(mǎn)
     */
    public boolean isFull(){
        return (rearPoint+1)%maxSzie == frontPoint;
    }
    /**
     * 向隊(duì)列中添加數(shù)據(jù)
     */
    public void add(int x){
        if (isFull()){
            System.out.println("當(dāng)前隊(duì)列已滿(mǎn)");
            return;
        }
        //添加數(shù)據(jù)
        array[rearPoint] = x ;
        //后移尾指針
        rearPoint = (rearPoint+1) % maxSzie;
        System.out.println("添加成功");
    }
    /**
     * 取出隊(duì)列中的數(shù)據(jù)
     */
    public int remove(){
        if (isEmpty()){
            throw new RuntimeException("當(dāng)前隊(duì)列為空");
        }
        //把隊(duì)頭的值賦值給臨時(shí)變量
        int x = array[frontPoint];
        //移除數(shù)據(jù)后頭指針需要向后移動(dòng) 時(shí)其指向新的隊(duì)頭
        frontPoint = (frontPoint+1) % maxSzie;
        System.out.println("移除成功");
        return x;
    }
    /**
     * 獲取隊(duì)列頭數(shù)據(jù)
     */
    public int gethead(){
        if (isEmpty()){
            throw new RuntimeException("當(dāng)前隊(duì)列為空");
        }
        return array[frontPoint];
    }
    /**
     * 遍歷隊(duì)列
     */
    public void show(){
        int x = 0;
       for (int i = frontPoint; i <= (rearPoint+maxSzie-frontPoint)%maxSzie; i++) {
            x++;
            System.out.println("隊(duì)列的第"+x+"個(gè)數(shù)據(jù)是"+array[i]);
        }
    }
}

public class QueueTest {
    public static void main(String[] args) {
        Queue queue = new Queue(5);
        Scanner scanner = new Scanner(System.in);
        char systemIn = ' ';
        boolean noEnd = true;
        while (noEnd){
            System.out.println("a:add(添加數(shù)據(jù))");
            System.out.println("r:remove(刪除數(shù)據(jù))");
            System.out.println("h:head(獲取隊(duì)頭)");
            System.out.println("s:show(遍歷隊(duì)列)");
            System.out.println("e:exit(退出程序)");
            System.out.println("請(qǐng)輸入字符");
            systemIn = scanner.next().charAt(0);
            switch (systemIn){
                case 'a':
                    System.out.println("請(qǐng)輸入入隊(duì)的數(shù)據(jù)(數(shù)字)");
                    int x = Integer.parseInt(scanner.next());
                    queue.add(x);
                    break;
                case 'r':
                    queue.remove();
                    break;
                case 'h':
                    int head = queue.gethead();
                    System.out.println("隊(duì)頭是"+head);
                    break;
                case 's':
                    queue.show();
                    break;
                case 'e':
                    noEnd = false;
                    break;
            }
        }
    }
}