static void Test_Case2()
        {
            CustomQueue <int> int_queue = new CustomQueue <int>();

            int_queue.enqueueing(1);
            int_queue.enqueueing(2);
            int_queue.enqueueing(3);
            int_queue.foreach_print();

            int_queue.dequeueing();
            int_queue.dequeueing();
            int_queue.dequeueing();
            int_queue.foreach_print();

            int_queue.enqueueing(4);
            int_queue.enqueueing(5);
            int_queue.foreach_print();
        }