#include<stdio.h>
#include<stdlib.h>
#define queuesize 4
int q[queuesize];
void enqueue(int );
void dequeue();
void display();
int r=-1;
int f=0;
int count=0;
int main()
{
    int ch,item;
    printf("\n");
    while(1)
    {
        scanf("%d",&ch);
        switch(ch)
        {
            case 1 : scanf("%d",&item);
                     enqueue(item);break;
            case 2 : dequeue();break;
            case 3 : display();break;
            case 4 : exit(0);
            default: printf("Invalid Choice\n");     
        }
    }
    return 0;
}

void enqueue(int item)
{
    
    if(count==queuesize)
    {
        printf("Circular Queue overflow cannot enqueue\n");
        return;
    }
    r=(r+1)%queuesize;
    q[r]=item;
    count=count+1;
}

void dequeue()
{
    if(count==0)
    {
        printf("Circular Queue Underflow cannot dequeue\n");
        return;
    }
    printf("Dequeued element is:%d\n",q[f]);
    f=((f+1)%queuesize);
    count=count-1;
}

void display()
{
    if(count==0)
    {
        printf("Circular Queue is empty nothing to display\n");
        return;
    }
    for(int i=0;i<count;i++)
    {
        printf("%d ",q[(f+i)%queuesize]);
       // f=(f+i)%queuesize;
    }
    printf("\n");
}