public void customer() { for (; ;) { Console.WriteLine("\n\t\tWelcome to Online Shop System Customet Login"); Console.WriteLine("--------------------------------------------------------------"); Console.WriteLine("1.Login\n2.Register\n3.View Products\n4.Add to Cart\n"); int choice = Convert.ToInt32(Console.ReadLine()); switch (choice) { case 1: int authorise = authenticationcustomerHandler.Login(); if (authorise == 2) { CustomerOptions(); } break; case 2: customerHandler.Register(); break; case 3: marketingPersonHandler.ViewProduct(); break; case 4: break; default: break; } } }