class_queue.cpp

#include<bits/stdc++.h>

using namespace std ;

#define M 500
class _queue
{
    int arr[M], top, rear;
public:
    _queue()
    {
        top   =  rear = -1;
    };
    void push(int a)
    {
        if(rear ==  M )
        {
            cout <<"overflow\n";
            return ;
        }
        if(top ==  -1)
            top++;

        rear++ ;
        arr[rear ] =  a;
        cout << "Item inserted to queue : " << a << endl ;

    }
    void pop(void )
    {
        if(top >  rear  || rear == -1)
        {
            cout << "Queue empty\n";
            top =  rear = -1;
            return ;
        }
        cout<< "Deleting item : " << arr[top ] << endl;
        top++;
    }
    void front()
    {
        if(top ==  -1 || top > rear )
            cout << "queue empty" << endl;
        else
            cout << arr[top ] << endl ;
    }
};

void input()
{
    _queue q ;

    int i, j,k ;
    while(1)
    {
        int choice, item ;
        cout <<"Enter choice (0/1)" << endl;
        cout <<"0 - to delete from queue :" << endl;
        cout <<"1  -  to insert into queue or " << endl;
        cout <<"2 - to show front  :" << endl;

        cin >> choice ;
        if(choice ==  1)
        {
            cout <<"Enter item\n";
            cin >> item ;
            q.push(item );
        }

        else if(choice ==  0) q.pop();
        else q.front();
        cout <<"\n" << endl;
    }
}

int main()
{
    input();
    /*
        _queue q ;
        q.push(11);
        q.push(12);
        q.push(13);
        q.front();
        q.pop();
        q.pop();
        q.pop();
        q.pop();

    */

    return 0 ;
}