How can I implement a queue in C?

How can I implement a queue in C?

To implement a queue in C, you can use a linked list or an array. Which method would you prefer?

I think using an array would be simpler. Can you show me an example?

Sure! Here's a basic implementation using an array:

#define MAX 100

struct Queue {
    int items[MAX];
    int front, rear;
};

void initQueue(struct Queue* q) {
    q->front = -1;
    q->rear = -1;
}

int isFull(struct Queue* q) {
    return q->rear == MAX - 1;
}

int isEmpty(struct Queue* q) {
    return q->front == -1;
}
}

void enqueue(struct Queue* q, int value) {
    if (isFull(q)) {
        printf("Queue is full!\n");
        return;
    }
    if (isEmpty(q)) {
        q->front = 0;
    }
    q->rear++;
    q->items[q->rear] = value;
}

int dequeue(struct Queue* q) {
    if (isEmpty(q)) {
        printf("Queue is empty!\n");
        return -1;
    }
    int item = q->items[q->front];
    if (q->front >= q->rear) {
        q->front = -1;
        q->rear = -1;
    } else {
        q->front++;
    }
    return item;
}

What about the functions to check if the queue is full or empty?

The functions isFull and isEmpty are included in the example. They check the queue's state based on the front and rear indices. Would you like to know more about how to use these functions?