# 第一種

#include <iostream>
using namespace std;

const int MAX_SIZE = 5;

class CircularQueue
{
private:
    int front, rear;
    int queue[MAX_SIZE];

public:
    CircularQueue()
    {
        front = rear = -1;
    }

    bool isEmpty()
    {
        return front == -1;
    }

    bool isFull()
    {
        return (front == 0 && rear == MAX_SIZE - 1) || (rear == (front - 1) % (MAX_SIZE - 1));
    }

    void enqueue(int value)
    {
        if (isFull())
        {
            cout << "[佇列已滿，中斷程式]" << endl;
            exit(0);
        }

        if (isEmpty())
            front = rear = 0;
        else
            rear = (rear + 1) % MAX_SIZE;

        cout << "請輸入一個值以存入佇列，欲取出值請輸入-2，(結束請輸入-1)" << endl;  // 修改提示訊息
        queue[rear] = value;
        cout << "加入佇列值[" << value << "]" << endl;
    }

    void dequeue()
    {
        if (isEmpty())
        {
            cout << "[佇列已經空了]" << endl;
            exit(0);
        }

        cout << "取出佇列值[" << queue[front] << "]" << endl;
        queue[front] = 0;

        if (front == rear)
            front = rear = -1;
        else
            front = (front + 1) % MAX_SIZE;
    }

    void display()
    {
        if (isEmpty())
        {
            cout << "[佇列已經空了]" << endl;
            return;
        }

        int i = front;
        do
        {
            cout << "[" << queue[i] << "]";
            i = (i + 1) % MAX_SIZE;
        } while (i != (rear + 1) % MAX_SIZE);

        cout << endl;
    }
};

int main()
{
    CircularQueue cq;
    int choice, value;

    do
    {
        cout << "請輸入一個值以存入佇列，欲取出值請輸入-2，(結束請輸入-1)\n請選擇操作: ";
        cin >> choice;

        switch (choice)
        {
        case -1:
            cout << "程式結束" << endl;
            cq.display();
            break;
        case -2:
            cq.dequeue();
            break;
        default:
            cq.enqueue(choice);
            break;
        }
    } while (choice != -1);

    return 0;
}

# 第二種改老師的的?

#include <iostream>
using namespace std;

const int SIZE = 5; 

int main()
{
    int front, rear, val = 0, queue[SIZE] = {0};
    front = rear = -1;

    while (true)
    {
        cout << "請輸入一個值以存入佇列，欲取出值請輸入-2，(結束請輸入-1): ";
        cin >> val;

        if (val == -1)
        {
            cout << "程式結束。" << endl;
            break;
        }
        else if (val == -2) // 取出值
        {
            if (front == -1)
            {
                cout << "[佇列已經空了]" << endl;
                break;
            }

            cout << "取出佇列值[" << queue[front] << "]" << endl;

            if (front == rear)
            {
                front = rear = -1; // 重置表示對列已空
            }
            else
            {
                front = (front + 1) % SIZE; // 循環對列的前進
            }
        }
        else 
        {
            if ((rear + 1) % SIZE == front)
            {
                cout << "[佇列已經滿了]" << endl;
            }
            else
            {
                if (front == -1)
                {
                    front = 0;
                }
                rear = (rear + 1) % SIZE;
                queue[rear] = val;
            }
        }
    }

    // 輸出對列中剩餘的數據
    cout << "\n佇列剩餘資料:" << endl;
    if (front == -1)
    {
        cout << "佇列已經空了" << endl;
    }
    else
    {
        int current = front;
        do
        {
            cout << "[" << queue[current] << "]";
            current = (current + 1) % SIZE;
        } while (current != (rear + 1) % SIZE);
    }
    cout << endl;

    return 0;
}