What are queues in C programming?

What are queues in C programming?

Queues are data structures that follow the First In First Out (FIFO) principle, where the first element added is the first to be removed.

How do I implement a queue in C?

You can implement a queue using arrays or linked lists. Would you like an example using one of these methods?

Yes, please provide an example using linked lists.

Sure! Here's a simple implementation of a queue using a linked list in C:

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

struct Node {
    int data;
    struct Node* next;
};

struct Queue {
    struct Node* front;
    struct Node* rear;
};

struct Queue* createQueue() {
    struct Queue* q = (struct Queue*)malloc(sizeof(struct Queue));
    q->front = q->rear = NULL;
    return q;
}

void enqueue(struct Queue* q, int value) {
    struct Node* temp = (struct Node*)malloc(sizeof(struct Node));
    temp->data = value;
    temp->next = NULL;
    if (q->rear == NULL) {
        q->front = q->rear = temp;
        return;
    }
    q->rear->next = temp;
    q->rear = temp;
}

int dequeue(struct Queue* q) {
    if (q->front == NULL) return -1;
    struct Node* temp = q->front;
    int value = temp->data;
    q->front = q->front->next;
    if (q->front == NULL) q->rear = NULL;
    free(temp);
    return value;
}

int main() {
    struct Queue* q = createQueue();
    enqueue(q, 10);
    enqueue(q, 20);
    printf("Dequeued: %d\n", dequeue(q));
    return 0;
}

This code creates a queue, enqueues two elements, and then dequeues one.

What are the advantages of using queues?

Queues are useful for managing tasks in a specific order, handling asynchronous data, and implementing algorithms like breadth-first search.