Circle Queue

// ConsoleApplication9.cpp : 定義主控台應用程式的進入點。
//

#include "stdafx.h"
#include <iostream>
using namespace std;
#define MAX 5

class queue{
public:
    void enqueue(int);
    void show(void);
    void dequeue(void);
private:
    int cq[MAX];
    int start=MAX-1;
    int end = MAX - 1;
    bool tag=0;
};

void queue::show(void)
{
    cout << "\nQueue list: ";
    if (tag == 0)
    {
        for (int i = (start + 1) % MAX; i != (end + 1) % MAX; i = (i + 1) % MAX)
        {
            cout << cq[i];
        }
    }
    else
    {
        int i = (start + 1) % MAX;
        cout << cq[i];
        i = (i + 1) % MAX;
        for (; i != (end + 1) % MAX; i = (i + 1) % MAX)
        {
            cout << cq[i];
        }
    }

    cout << endl;
    for (int i = 0; i < MAX; i++)
    {
        cout << cq[i];
        if (i == start)
            cout << "  <-start";
        if (i == end)
            cout << "  <-end";
        cout << endl;
    }
}
void queue::enqueue(int in)
{
    if (start == end && tag == 1)
        cout << "\nQueue is full when inserting " << in << "!\n";
    else{
        end = ( end+1 ) % MAX;
        cout << "\ninsert "<<in<<"\n";
        cq[end]=in;
        if (start == end)
            tag = 1;
    }
}
void queue::dequeue(void)
{
    if (start == end&&tag == 0)
    {
        cout << "\nQueue is empty!\n";
    }
    else
    {
        start = (start + 1) % MAX;
        cout << "\nDeque " << cq[start] << endl;
        tag = 0;
    }
}


int main()
{
    queue qu1;
    for (int i = 0; i < 3; i++)
    {
        qu1.enqueue(i+1);
        qu1.show();
    }
    for (int i = 0; i < 2; i++)
    {
        qu1.dequeue();
        qu1.show();
    }
    for(int i = 0; i < 5; i++)
    {
        qu1.enqueue(i + 4);
        qu1.show();
    }
    return 0;
}