Simple iterator for the positive integers.

Incrementer.cs

public class Incrementer : IEnumerable<int>
{
  public IEnumerator<int> GetEnumerator()
  {
    return new IncrementingEnumerator();
  }

  IEnumerator IEnumerable.GetEnumerator()
  {
    return GetEnumerator();
  }
}

public class IncrementingEnumerator : IEnumerator<int>
{
  private int _n;

  public bool MoveNext()
  {
    ++_n;
    return true;
  }

  public int Current
  {
    get { return _n; }
  }

  object IEnumerator.Current
  {
    get { return Current; }
  }

  public void Dispose() { }

  public void Reset()
  {
    _n = 0;
  }
}