static void Main(string[] args) { Operation operation = new Operation(); operation.ReadAndStoreCountries(); var country = new Country(); country.Name = "Ukraine"; country.IsTelenorSupported = false; operation.AddCountry(country); List <Country> countriesToEdit = new List <Country> { new Country() { Name = "Denmark", IsTelenorSupported = true }, new Country() { Name = "Hungary", IsTelenorSupported = true } }; countriesToEdit.ForEach(c => { operation.ChangeCountry(c); }); operation.PrintCountries(); Console.ReadKey(); }