public static void Main(string[] args) { if (!File.Exists(_settings.Path)) { _settings.CreateDefaultFileSettings(); } _settings.GetSettingsFromFile(); GetArgs(args, out double?first, out double?second, out string functionName); SetValueIfNull(ref first, ref second, ref functionName); if (!CheckFunctionName(functionName)) { Console.Write("The configuration file does not contain this function"); return; } SetCurrentFunction(functionName); double result; Calculator calculate = new Calculator(functionName); try { result = calculate.TestFunction(first.Value, second.Value); } catch (Exception ex) { Console.WriteLine($"There is a problem: {ex.Message}. The app is closing"); Console.ReadKey(); return; } Console.WriteLine(result.ToString("G", CultureInfo.InvariantCulture)); Console.ReadKey(); }