private void OnExecute(CommandLineApplication app) { if (string.IsNullOrEmpty(CurrencyPair)) { app.ShowHelp(); } var currencies = CurrencyPair.Split('/'); var baseCurrencyISO = currencies[0]; var quoteCurrencyISO = currencies[1]; try { var exchanger = new RateExchanger(new HardCodedCurrencyPairRepository()); var result = exchanger.Exchage(baseCurrencyISO, quoteCurrencyISO, (decimal)Amount); Console.WriteLine(result.Amount); } catch (RateNotFoundException) { Console.WriteLine("Rate not found."); } catch (Exception) { Console.WriteLine("Unknown error."); } }