/**
 * description:數(shù)組實(shí)現(xiàn)環(huán)形隊(duì)列
 * author: xiaowang
 * */
public class MyQueue<E> {
    // 隊(duì)列最大個(gè)數(shù)
    private int size;
    // 元素真實(shí)個(gè)數(shù)
    private int number;
    // 頭指針，指向隊(duì)列的第一個(gè)元素即隊(duì)頭
    private int front;
    // 尾指針，指向隊(duì)尾的后一個(gè)元素(非隊(duì)尾)
    private int rear;
    // 隊(duì)列具體值
    private Object[] values;
    // 隊(duì)列滿標(biāo)記，當(dāng)隊(duì)列是滿的時(shí)候?yàn)閠rue
    private boolean isFullFlag;

    /**構(gòu)造器*/
    public MyQueue(int size){
        if (size<0){
            throw new RuntimeException("初始化隊(duì)列時(shí)，隊(duì)列最大元素個(gè)數(shù)不能為負(fù)");
        }
        this.front  = 0;
        this.rear = 0;
        this.number = 0;
        this.isFullFlag = false;
        this.size = size;
        this.values = new Object[size];

    }

    /**往隊(duì)列里添加元素 添加成功返回true 失敗返回false*/
    public boolean addToQueue(E e){
        // 判斷隊(duì)列是否已經(jīng)滿了
        if (isFullFlag){
            System.out.println("隊(duì)列已滿,無法繼續(xù)添加元素");
            return false;
        }
        // 添加元素
        values[rear] = e;
        // 元素個(gè)數(shù)加一
        number++;
        // 尾指針后移一位，若已經(jīng)指向數(shù)組最后的下表，則重新指向0
        if (rear == size-1){
            rear = 0;
        }else{
            rear++;
        }
        // 添加完這個(gè)元素，判斷隊(duì)列是否已經(jīng)滿了，若滿則標(biāo)記為true
        if (rear==front){
            isFullFlag = true;
        }
        return true;
    }
    /**從隊(duì)列里取出數(shù)據(jù)，隊(duì)頭數(shù)據(jù)*/
    public E getFromQueue(){
        // 判斷隊(duì)列是否為空
        if (number==0||size==0){
            System.out.println("隊(duì)列為空，無法從隊(duì)列中獲取數(shù)據(jù)");
            return null;
        }
        // 臨時(shí)變量
        E e = (E) values[front];
        // 隊(duì)頭置空
        values[front] = null;
        // 個(gè)數(shù)減一
        number--;
        // 頭指針后移，若已經(jīng)指向數(shù)組最后的下表，則重新指向0
        if (front==size-1){
            front = 0;
        }else {
            front++;
        }
        // 取隊(duì)列之前若是滿的狀態(tài)，則更新狀態(tài)
        if (isFullFlag){
            isFullFlag = false;
        }
        return e;
    }
    /**獲取目前有幾個(gè)元素正在進(jìn)行排隊(duì)*/
    public int getNumber(){
        return number;
    }
    /**獲取隊(duì)列的最大個(gè)數(shù)*/
    public int getSize(){
        return size;
    }
    /**查看隊(duì)列在數(shù)組里保存的詳細(xì)情況*/
    public String toString(){
        StringBuffer valueStr = new StringBuffer();
        valueStr.append("[");
        for (int i = 0; i < size; i++) {
            if (i!=size-1){
                valueStr.append(values[i]+",");
            }else{
                valueStr.append(values[i]+"]");
            }
        }
        return valueStr.toString();
    }
}

public class TestQueue {

    public static void main(String[] args) {
        MyQueue<String> queue = new MyQueue<String>(5);
        Scanner scanner = new Scanner(System.in);
        Scanner scanner2 = new Scanner(System.in);
        boolean isCan = true;
        while (isCan){
            System.out.println("歡迎來到小王排隊(duì)系統(tǒng)，您可以使用以下功能。\n添加：1；取出：2；展示：3；獲取排隊(duì)個(gè)數(shù)：4；退出：0。");
            int flag = scanner.nextInt();
            switch (flag){
                case 1 :
                    System.out.println("請輸入一個(gè)數(shù)據(jù)：");
                    String data = scanner2.nextLine();
                    boolean isSuccess = queue.addToQueue(data);
                    if (isSuccess){
                        System.out.println("添加成功~~~");
                    }
                    break;
                case 2 :
                    String dataFromQueue = queue.getFromQueue();
                    if (dataFromQueue!=null){
                        System.out.println("本次取出的數(shù)據(jù)為："+dataFromQueue);
                    }
                    break;
                case 3 :
                    System.out.println("隊(duì)列詳情為：\n"+queue.toString());
                    break;
                case 4 :
                    System.out.println("目前有"+queue.getNumber()+"個(gè)元素正在進(jìn)行排隊(duì)");
                    break;
                default:
                    isCan = false;
                    System.out.println("已退出...");
                    break;
            }
        }

    }
}