KKStr   FeatureNumList::ToHexString (FileDescConstPtr  fileDesc)  const
{
  BitString  bs (fileDesc->NumOfFields ());
  ToBitString (bs);
  return  bs.HexStr ();
}  /* ToHexString */
KKStr   FeatureNumList::ToHexString ()  const
{
  BitString  bs (maxFeatureNum + 1);
  ToBitString (bs);
  return  bs.HexStr ();
}  /* ToHexString */