44_circular_queue.c

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

// Fixed typo in structure name
struct circularQueue {
    int size;
    int f;
    int r;
    int *arr;
};

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

int isFull(struct circularQueue *q) {
    if((q->r + 1) % q->size == q->f) {
        return 1;
    } else {
        return 0;
    }
}

void traverse(struct circularQueue *q) {
    if (isEmpty(q)) {
        printf("Queue is empty\n");
        return;
    }
    int i = (q->f + 1) % q->size;
    printf("Elements in the queue: ");
    while (i != (q->r + 1) % q->size) {
        printf("%d ", q->arr[i]);
        i = (i + 1) % q->size;
    }
    printf("\n");
}

void enqueue(struct circularQueue *q, int val) {
    if(isFull(q)) {
        printf("This Queue is full\n");
    } else {
        q->r = (q->r + 1) % q->size;
        q->arr[q->r] = val;
    }
}

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

int main() {
    // Fixed typo in allocation
    struct circularQueue *q = (struct circularQueue *)malloc(sizeof(struct circularQueue));
    q->size = 3;
    q->f = q->r = 0;
    q->arr = (int*)malloc(q->size * sizeof(int));
    // if(isEmpty(q)) {
    //     printf("Queue is empty\n");
    // }

    //Enqueue few elements
    enqueue(q,12);
    enqueue(q,2);
    traverse(q);

    //Dequeue few elements
    printf("Dequeuing element %d\n",dequeue(q));
    // enqueue(q,6);

    //Traverse the queue
    traverse(q);

    free(q->arr);
    free(q);
    return 0;
}