private static void FindPerson(IPhoneBookRepository phoneBook, string firstName, string lastName) { var person = phoneBook.FindPerson(firstName, lastName); if (person != null) { Console.WriteLine("Result Person Found:"); Console.WriteLine(String.Format("Name: {0} Phone: {1}, Address: {2}", person.FirstName + " " + person.LastName, person.PhoneNumber, person.Address)); } }