C program to implement Circular Queue operations

Below C program implements various Circular Queue operations

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#include<stdio.h>
#define max 3
int q[10],front=0,rear=-1;
void main()
{
    int ch;
    void insert();
    void delet();
    void display();
    clrscr();
    printf("\nCircular Queue operations\n");
    printf("1.insert\n2.delete\n3.display\n4.exit\n");
    while(1)
    {
        printf("Enter your choice:");
        scanf("%d",&ch);
        switch(ch)
        {
        case 1: insert();
            break;
        case 2: delet();
            break;
        case 3:display();
            break;
        case 4:exit();
        default:printf("Invalid option\n");
        }
    }
}
 
void insert()
{
    int x;
    if((front==0&&rear==max-1)||(front>0&&rear==front-1))
        printf("Queue is overflow\n");
    else
    {
        printf("Enter element to be insert:");
        scanf("%d",&x);
        if(rear==max-1&&front>0)
        {
            rear=0;
            q[rear]=x;
        }
        else
        {
            if((front==0&&rear==-1)||(rear!=front-1))
                q[++rear]=x;
        }
    }
}
void  delet()
{
    int a;
    if((front==0)&&(rear==-1))
    {
        printf("Queue is underflow\n");
        getch();
        exit();
    }
    if(front==rear)
    {
        a=q[front];
        rear=-1;
        front=0;
    }
    else
        if(front==max-1)
        {
            a=q[front];
            front=0;
        }
        else a=q[front++];
        printf("Deleted element is:%d\n",a);
}
 
void display()
{
    int i,j;
    if(front==0&&rear==-1)
    {
        printf("Queue is underflow\n");
        getch();
        exit();
    }
    if(front>rear)
    {
        for(i=0;i<=rear;i++)
            printf("\t%d",q[i]);
        for(j=front;j<=max-1;j++)
            printf("\t%d",q[j]);
        printf("\nrear is at %d\n",q[rear]);
        printf("\nfront is at %d\n",q[front]);
    }
    else
    {
        for(i=front;i<=rear;i++)
        {
            printf("\t%d",q[i]);
        }
        printf("\nrear is at %d\n",q[rear]);
        printf("\nfront is at %d\n",q[front]);
    }
    printf("\n");
}
getch();

16 Responses to “C program to implement Circular Queue operations”

  1. prince sharma

    display func will not work when u add one element in queue and thn u delete it….only one element

    Reply
  2. thank you so much…u are doing such a nice work helping needy student…love ur site :)

    Reply
  3. #include
    #include
    #include
    # define max 3

    int front=0,rear=-1;
    int cq[max],count=0;

    void cqinsert()
    {
    int ele;

    if(count==max)
    {
    printf(“cq is full\n”);
    return;
    }
    printf(“enter the element\n”);
    scanf(“%d”,&ele);
    rear=(rear+1)%max;
    cq[rear]=ele;
    count++;
    }
    void cqdelete()
    {
    if(count==0)
    {
    printf(“cq is empty\n”);
    return;
    }
    printf(“element deleted is %d”,cq[front]);
    front =(front+1)%max;
    count–;
    }
    void cqdisplay()
    {
    int j=front,i;
    if(count==0)
    {
    printf(“cq is empty\n”);
    return;
    }
    for(i=1;i<=count;i++)
    {
    printf("%d\t",cq[j]);
    j=(j+1)%max;
    }
    }
    void main()
    {
    int ch;
    clrscr();
    printf("1:insert 2:delete 3:display default :exit\n");
    do

    {
    printf("enter choice\n");
    scanf("%d",&ch);
    switch(ch)
    {
    case 1: cqinsert();
    break;
    case 2: cqdelete();
    break;
    case 3: cqdisplay();
    break;
    case 4: exit(0);
    }
    }while(ch<=4) ;
    getch();
    }

    Reply
  4. I need c program to implement circular queue.Consider element
    of type string

    Reply

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