program to implement circular queue

#include<stdio.h>
#define MAX 10
int que[MAX];
int front=-1;
int rear=-1;
void insert();
void del();
void disp();
 main()
{
    int ch;
    while(1)
    {
    printf("\n..................MENU................\n");
    printf("select your choice\n");
    printf("1.insert\n");
    printf("2.delete\n");
    printf("3.display\n");
    printf("4.exit\n");
    printf("enter your choice:");
    scanf("%d",&ch);
    switch(ch)
    {

        case 1:
        insert();
        break;
        case 2:
        del();
        break;
        case 3:
        disp();
        break;
        case 4:
        exit(1);
        default :
        printf("invalid choice\n");

         }
    }
}
void insert()
{
    int val;
    if((front==0&&rear==MAX-1)||(front==rear+1))
    {
    printf("queue overflow\n");
    return;
    }
    if(front==-1)
    {
        front=0;
        rear=0;

    }
    else
        if(rear==MAX-1)
        {
            rear=0;
        }
        else
        rear=rear+1;
        printf("enter the element for insertion in queue:");
        scanf("%d",&val);
        que[rear]=val;

}
void del()
{
    if(front==-1)
    {
        printf("queue underflow\n");
        return;

    }
    printf("element deleted from queue is=%d",que[front]);
    if(front==rear)
    {
        front=-1;
        rear=-1;
    }
    else
        if(front==MAX-1)
        {
            front=0;
        }
        else
        front=front+1;

}
void disp()
{
    int f=front,r=rear;
    if(front==-1)
    {
        printf("queue is empty\n");
        return;

    }
    printf("queue elements:\n");
    if(f<=r)
    while(f<=r)
    {
        printf("%d\t",que[f]);
        f++;
    }
    else
    {
        while(f<=MAX-1)
        {
            printf("%d\t",que[f]);
            f++;

        }
        f=0;
        while(f<=r)
        {

            printf("%d\t",que[f]);
            f++;
        }
    }
}



                         OUTPUT

..................MENU................
select your choice
1.insert
2.delete
3.display
4.exit
enter your choice:1
enter the element for insertion in queue:1

..................MENU................
select your choice
1.insert
2.delete
3.display
4.exit
enter your choice:1
enter the element for insertion in queue:2

..................MENU................
select your choice
1.insert
2.delete
3.display
4.exit
enter your choice:1
enter the element for insertion in queue:3

..................MENU................
select your choice
1.insert
2.delete
3.display
4.exit
enter your choice:3
queue elements:
1       2       3
..................MENU................
select your choice
1.insert
2.delete
3.display
4.exit
enter your choice:2
element deleted from queue is=1
..................MENU................
select your choice
1.insert
2.delete
3.display
4.exit
enter your choice:2
element deleted from queue is=2
..................MENU................
select your choice
1.insert
2.delete
3.display
4.exit
enter your choice:2
element deleted from queue is=3
..................MENU................
select your choice
1.insert
2.delete
3.display
4.exit
enter your choice:1
enter the element for insertion in queue:8

..................MENU................
select your choice
1.insert
2.delete
3.display
4.exit
enter your choice:3
queue elements:
8
..................MENU................
select your choice
1.insert
2.delete
3.display
4.exit
enter your choice:4

Process returned 1 (0x1)   execution time : 53.552 s
Press any key to continue.