circular linked list

#include<stdio.h>
#include<conio.h>
#define size 5
int q[size],rear=-1,front=-1,item;
void insert();
void delete();
void display();
void insert()
{
if((front==0&&rear==-1)||(front==rear+1))
printf("queue is full");
else
{
printf("enter the element");
scanf("%d",&item);
if(rear==-1)
{
rear=0;
front=0;
}
else if(rear==size-1)
rear=0;
else rear++;
q[rear]=item;
printf("the inserted %d",item);
}
}
void delete()
{
if(front==-1)
printf("queue is empty");
else
{
item=q[front];
if(front==rear)
{
front=-1;
rear=1;
}
else if(front!=size-1)
front=0;
else
front++;
printf("%d element",item);
}
}
void display()
{
int i;
if(front==-1)
printf("queue is empty");
else if(front>rear)
{
for(i=front;i<=size;i++)
printf("%d",q[i]);
for(i=0;i<=rear;i++)
printf("%d",q[i]);
}
else
{
for(i=front;i<=rear;i++)
printf("%d",q[i]);
}
}
void main()
{
int i;
clrscr();
do
{
printf("\n1.insert\n2.delete\n3.display\n4.exit");
printf("\nenter your choice");
scanf("%d",&i);
switch(i)
{
case 1:insert();
break;
case 2:delete();
break;
case 3:display();
break;
case 4:exit(0);
break;
default :printf("invalid option");
} }while(i!=4);
getch();
}