public void StartApplication() { start: IRestro iRestro = chooseRestro(); while (true) { Console.WriteLine("1. Admin"); Console.WriteLine("2. Customer"); Console.WriteLine("3. Back to Restro choice"); Console.WriteLine("Please Enter Your Choice"); int choice = Convert.ToInt32(Console.ReadLine()); switch (choice) { case 1: iRestro.ShowAdmin(); break; case 2: User user = new User(); user.ShowCustomer(iRestro); break; case 3: goto start; default: Console.WriteLine("Wrong choice"); Environment.Exit(0); break; } } Console.ReadKey(); }