public static string GetUserDataByEnteringPasses() { Console.Clear(); string userData; string login; string password; Console.WriteLine("Witaj! Zaloguj sie na konto"); Console.Write("Login: "******"Password: "******"Librarian")) { userData = TextFileHandler.GetLibrarianDataFromFile(UserId); return(userData + $",{password},{login}"); } else if (login.Contains("User")) { userData = TextFileHandler.GetOrdinaryUserDataFromFile(UserId); return(userData + $",{password},{login}"); } } return(null); }