        if (op == 'e')
        {
            cin >> element;
            ptr = (int*)malloc(sizeof(int));
            *ptr = element;
            pthread_rwlock_fcfs_queue_enqueue(queue, ptr);
        }
        else if (op == 'd')
        {
            ptr = (int *)pthread_rwlock_fcfs_queue_dequeue(queue);
            if (ptr == NULL)
            {
                cout << "Queue is empty!\n";
            }
            else