Circular Queue

GXTechno Tags: c, data, structure. queue, circular

/*circular queue using array*/
#include<stdio.h>
#include<conio.h>
#define MAXSIZE 5
int cq[10];
int front=-1,rear=0;
int choice;
char ch;
void main()
{
clrscr();
do
{

         printf("--------1.Insert-------\n");
         printf("------- 2. Delete--------\n");
         printf("------- 3. Display--------\n");
         printf("-------4.exit------------\n");
         printf("Enter your choice\n");
         scanf("%d",&choice);
switch(choice)
{
case 1 : cqinsert();
break;
case 2 : cqdelete();
break;
case 3 : cqdisplay();
break;
case 4: return;
}
        fflush(stdin);
        }
       while(choice!=4);
           }
cqinsert()
{
       int num;
       if(front==(rear+1)%MAXSIZE)
     {
      printf("Queue is full\n");
      return;
     }
else
       {
         printf("Enter the element to be inserted\n");
         scanf("%d",&num);
        if(front==-1)
             front=rear=0;
        else

             rear=(rear+1) % MAXSIZE;
             cq[rear]= num;

       }
  return;
}
int cqdelete()
{
int num;
       if(front==-1)
      {
     .
         printf("Queue is Empty\n");
         return;
      }
  else
       {
      num=cq[front];
      printf("Deleted element is =%d\n",cq[front]);

         if(front==rear)
         front=rear=-1;
         else
           front=(front+1)%MAXSIZE;
       }
     return(num);

}
cqdisplay()
{
int i;
if(front==-1)
{
printf("Queue is empty\n");
return;
}
else
{
printf("\nThe status of the queue\n");
for(i=front;i<=rear;i++)
{
printf("%d\n",cq[i]);
}
}
if(front>rear)
{
    for(i=front;i<MAXSIZE;i++)
    {
    printf("%d\n",cq[i]);
    }
    for(i=0;i<=rear;i++)
    {
    printf("%d\n",cq[i]);
    }
}
printf("\n");
}

/*output of the program*/
--------1.Insert-------
------- 2. Delete--------
------- 3. Display--------
-------4.exit------------
Enter your choice
1
Enter the element to be inserted
2
--------1.Insert-------
------- 2. Delete--------
------- 3. Display--------
-------4.exit------------
Enter your choice
1
Enter the element to be inserted
5
--------1.Insert-------
------- 2. Delete--------
------- 3. Display--------
-------4.exit------------
Enter your choice
2
Deleted element is =2
--------1.Insert-------
------- 2. Delete--------
------- 3. Display--------
-------4.exit------------
Enter your choice
3

The status of the queue
5

--------1.Insert-------
------- 2. Delete--------
------- 3. Display--------
-------4.exit------------
Enter your choice
4