linear n circular queue

#include<stdio.h>
#include<conio.h>
#define max 3

struct queue
{
    int item[max];
    int front;
    int rear;
    int count;
}p;





void main()
{
    int a,b,i,s=1,f=1,j;
    p.front=(max-1);
    p.rear=(max-1);
    p.count=0;
    printf("enter \n1.for linear queue \n2.for circular queue\n");
    scanf("%d",&a);
    switch(a)
    {
    case 1:
        p.front=0;
        p.rear=-1;
        p.count=0;
        do
        {
            printf("enter 1.to insert element 2.to delete element 3.to display queue\n");
            scanf("%d",&b);
            switch(b)
            {
                case 1:
                    if(p.rear==(max-1))
                    {
                        printf("the queue is full\n");
                        break;
                    }
                    p.rear++;
                    printf("enter the data element\n");
                    scanf("%d",&p.item[p.rear]);
                    break;

                case 2:
                    if(p.front>p.rear)
                    {
                        printf("queue is empty, cannot delete\n");
                        break;
                    }
                    printf("the element being deleted is %d\n",p.item[p.front]);
                    p.front++;
                    break;

                case 3:
                    if(p.front>p.rear)
                    {
                        printf("queue is empty\n");
                        break;
                    }
                    printf("elements of the queue are:\n");
                    i=(p.front);
                    while(i<=(p.rear))
                    {
                        printf("%d\n",p.item[i]);
                        i++;
                    }
                    break;

                default:
                    printf("invalid operator\n");
                    break;
            }
            printf("enter 0 to exit\n");
            scanf("%d",&i);
        }while(i!=0);
        break;

    case 2:
        p.front=(max-1);
        p.rear=(max-1);
        do
        {
            printf("enter 1.to insert element 2.to delete element 3.to display queue\n");
            scanf("%d",&b);
            switch(b)
            {
                case 1:
                    p.rear=((p.rear+1)%(max));
                    printf("index %d %d\n",p.rear,p.front);
                    if((p.rear==p.front)&&(p.count==max)&&(s==0))
                    {
                        printf("the queue is full\n");
                        p.rear--;
                        break;
                    }
                    printf("enter the data element\n");
                    scanf("%d",&p.item[p.rear]);
                    p.count++;
                    if(p.rear==p.front)
                    {
                        p.rear--;
                        s=0;
                    }
                    break;

                case 2:
                    if(p.count==0)
                    {
                        printf("queue is empty, cannot delete\n");
                        break;
                    }
                    if(f!=0)
                        p.front=(p.front+1)%max;

                    s=1;
                    printf("the element being deleted is %d\n",p.item[p.front]);
                    f=0;
                    p.count--;
                    p.front=((p.front+1)%(max));
                    break;

                case 3:
                    if(p.count==0)
                    {
                        printf("queue is empty\n");
                        break;
                    }
                    if(f!=0)
                        p.front=(p.front+1)%max;
                    printf("elements of the queue are:\n");
                    i=(p.front);
                    j=p.count;
                    while(j!=0)
                    {
                        printf("%d\n",p.item[i]);
                        i=((i++)%max);
                        j--;
                    }
                    if(f!=0)
                        p.front=(max-1);
                    break;

                default:
                    printf("invalid operator\n");
                    break;
            }
            printf("enter 0 to exit\n");
            scanf("%d",&i);
        }while(i!=0);
        break;

    default:
        printf("invalid operator\n");
        break;
    }
}