static void Main(string[] args) { if (args.Length > 0) { if (_bookCatalogValidator.IsValid(args[0])) { _activitiesManager = new ActivitiesManager(args[0]); _availableActivities = _activitiesManager.GetAvailableActivities().ToList(); Console.WriteLine(">>> Welcome to \"CleanCode\" Library! <<<"); string userAnswer = ""; do { Console.WriteLine("\nChoose what you want to do:"); for (int i = 0; i < _availableActivities.Count; i++) { Console.WriteLine($" {i + 1}: {_availableActivities[i]}"); } Console.WriteLine(" Q: Exit"); Console.Write("\nCommand: "); userAnswer = Console.ReadLine(); } while (HandleRequests(userAnswer)); } else { Console.WriteLine("[ERROR] The specified book catalog is invalid. Available formats: .xml or .json"); } } else { Console.WriteLine("[ERROR] Book catalog has not been provided. Available formats: .xml or .json"); } }