static void Main(string[] args)
        {
            Console.WriteLine("Welcome to order management system!");
            OrderService server = new OrderService();

            while (true)
            {
                try
                {
                    Console.Write("0.help \n1.add order\n2.delete order\n3.show orders\n4.change order information\n5.Search order\n");
                    int Controler = int.Parse(Console.ReadLine());
                    switch (Controler)
                    {
                    case 0:
                        break;

                    case 1:
                        server.addOrder();
                        break;

                    case 2:
                        Console.WriteLine("Please input the ID of the order you want to delete:");
                        server.delOrder(int.Parse(Console.ReadLine()));
                        break;

                    case 3:
                        server.displayAll();
                        break;

                    case 4:
                        Console.WriteLine("Please input the ID of the order you want to change");
                        server.changeOrder(int.Parse(Console.ReadLine()));
                        break;

                    case 5:
                        server.searchOrder();
                        break;

                    default:
                        break;
                    }
                }
                catch { }
            }
        }