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c code for queue using array

July ,7th ,2022
carray_queue
write a c code for queue using array

Write a menu-driven program to implement queue operations such as Enqueue, Dequeue, Peek, Display of elements, Is Empty, and IsFull using a static array.

Code

#include <stdio.h>
#include <stdlib.h>

struct queue
{
    int size;
    int f;
    int r;
    int *arr;
};

int isEmpty(struct queue q)
{
    if (q->r == q->f)
    {
        return 1;
    }
    return 0;
}

int isFull(struct queue *q)
{
    if (q->r == q->size - 1)
    {
        return 1;
    }
    return 0;
}

void enqueue(struct queue *q, int val)
{
    if (isFull(q))
    {
        printf("This Queue is full\n");
    }
    else
    {
        q->r++;
        q->arr[q->r] = val;
        printf("Enqued element: %d\n", val);
    }
}

int dequeue(struct queue *q)
{
    int a = -1;
    if (isEmpty(q))
    {
        printf("This Queue is empty\n");
    }
    else
    {
        q->f++;
        a = q->arr[q->f];
    }
    return a;
}

int peekF(struct queue *q)
{
    return q->arr[q->f];
}

int peekR(struct queue *q)
{
    return q->arr[q->r];
}

void display(struct queue *q)
{
    int k = q->f + 1;

    while (k != q->r)
    {
        printf("%d ", q->arr[k]);
        k++;
    }
    printf("%d ", q->arr[k]);
}

int main()
{
    struct queue q;
    int s;
    printf("enter the size of queue : ");
    scanf("%d", &s);
    q.size = s;
    q.f = q.r = 0;
    q.arr = (int *)malloc(q.size * sizeof(int));
    int c, i;
    while (1)
    {
        options:
        printf("\n1.enqueue\n");
        printf("2.dequeue\n");
        printf("3.Display element at the front\n");
        printf("4.Display element at the rear\n");
        printf("5.Display all elements of the queue\n");
        printf("6.isFull\n");
        printf("7.isEmpty\n");
        printf("8.Quit\n");
        printf("\nEnter your choice : ");
        scanf("%d", &c);

        switch (c)
        {
        case 1:
            printf("\nInput the element for adding in queue : ");
            scanf("%d", &i);
            enqueue(&q, i);
            break;
        case 2:
            i = dequeue(&q);
            printf("\nDeleted element is  %d\n", i);
            break;
        case 3:
            printf("\nElement at the front is %d\n", peekF(&q));
            break;
        case 4:
            printf("\nElement at the rear is %d\n", peekR(&q));
            break;
        case 5:
            display(&q);
            break;
        case 6:
            if (isFull(&q))
            {
                printf("Queue is full\n");
            }
            else
            {
                printf("Queue is not full\n");
            }
            break;
        case 7:
            if (isEmpty(&q))
            {
                printf("Queue is empty\n");
            }
            else
            {
                printf("Queue is not empty\n");
            }
            break;
        case 8:
            exit(1);
        default:
            printf("\nWrong choice\n");
        }
    }
    return 0;
}