public static void Operations(ListyIterator <string> collection) { while (true) { var command = Console.ReadLine(); var elementToPrint = String.Empty; if (command == "Move") { elementToPrint = collection.Move(); } else if (command == "HasNext") { elementToPrint = collection.HasNext(); } else if (command == "Print") { elementToPrint = collection.Print(); } else if (command == "PrintAll") { var toPrint = new StringBuilder(); foreach (var element in collection) { toPrint.Append(element + " "); } Console.Write(toPrint); } else if (command == "END") { break; } Console.WriteLine(elementToPrint); } }