9
Groups of Objects: Collection enumerator class
lpublic class SequenceCollection : IEnumerator
l{
l IntegerSequence sequence; int index;
l public SequenceCollection(IntegerSequence Sequence)
l {sequence=Sequence; index=sequence.Start-1;}
l public bool MoveNext()
l {++index; return (index>sequence.End)?false:true;}
l public object Current{
l get{
l    if (index<sequence.Start | index>sequence.End)
l       throw new InvalidOperationException(
l          "The selected IntegerSequence object is out of range");
l    return index;}
l }
l public void Reset() {index=sequence.Start-1;}
l}
l