public static void LogInUser() { bool isUserLoggedIn = false; var api = new API(); do { Console.Clear(); Console.Write("Enter user name:\n"); var userName = Console.ReadLine(); Console.Write("Enter password:\n"); var password = Console.ReadLine(); var result = api.Login(userName, password); if (result == null) { var input = LoginMessage.Error(); if (input != "") { Console.Clear(); break; } } else { LoginMessage.Success(userName); isUserLoggedIn = true; } } while (isUserLoggedIn == false); }