/* Program of circular queue using array*/
# include<stdio.h># define MAX 5
int cqueue_arr[MAX];
int front = -1;
int rear = -1;
main()
{
int choice;
while(1)
{
printf("1.Insert\n");
printf("2.Delete\n");
printf("3.Display\n");
printf("4.Quit\n");
printf("Enter your choice : ");
scanf("%d",&choice);
switch(choice)
{
case 1 :
insert();
break;
case 2 :
del();
break;
case 3:
display();
break;
case 4:
exit(1);
default:
printf("Wrong choice\n");
}/*End of switch*/
}/*End of while */
}/*End of main()*/
insert()
{
int added_item;
if((front == 0 && rear == MAX-1) || (front == rear+1))
{
printf("Queue Overflow \n");
return;
}
if (front == -1) /*If queue is empty */
{
front = 0;
rear = 0;
}
else
if(rear == MAX-1)/*rear is at last position of queue */
rear = 0;
else
rear = rear+1;
printf("Input the element for insertion in queue : ");
scanf("%d", &added_item);
cqueue_arr[rear] = added_item ;
}/*End of insert()*/
del()
{
if (front == -1)
{
printf("Queue Underflow\n");
return ;
}
printf("Element deleted from queue is : %d\n",cqueue_arr[front]);
if(front == rear) /* queue has only one element */
{
front = -1;
rear=-1;
}
else
if(front == MAX-1)
front = 0;
else
front = front+1;
}/*End of del() */
display()
{
int front_pos = front,rear_pos = rear;
if(front == -1)
{
printf("Queue is empty\n");
return;
}
printf("Queue elements :\n");
if( front_pos <= rear_pos )
while(front_pos <= rear_pos)
{
printf("%d ",cqueue_arr[front_pos]);
front_pos++;
}
else
{
while(front_pos <= MAX-1)
{
printf("%d ",cqueue_arr[front_pos]);
front_pos++;
}
front_pos = 0;
while(front_pos <= rear_pos)
{
printf("%d ",cqueue_arr[front_pos]);
front_pos++;
}
}/*End of else */
printf("\n");
}
