Difference between IEnumerable and IEnumerator

IEnumerable is an interface that has the definition one method named GetEnumerator which return an object of type IEnumerator.

public class OldEnumerable : IEnumerable

{

  public IEnumerator GetEnumerator()

  {

      return new OldEnumerator();

  }

}

Now let’s look at OldEnumerator

public class OldEnumerator : IEnumerator

{

  int x = 0;

  public object Current

  {

      get { return x; }

  }

  public bool MoveNext()

  {

      return x++ < 100;

  }

  public void Reset()

  {

      x = 0;

  }

}