IEnumerable

IEnumerable

  static IEnumerable<int> CreateSimpleIterator() {
            yield return 10;
            for (int i = 0; i < 3; i++) {
                yield return i;
                ;
            }

            yield return 20;
        }
        public static void Main(string[] args) {

            foreach (var item in CreateSimpleIterator()) {
              Console.WriteLine(item);   
            }

            Console.WriteLine("ok");
            Console.ReadKey();
        }