Robot* otherRobotAt(Robot* rp) const
//      If there is at least one robot (other than the one rp points to)
//      at the same (r,c) coordinates as the one rp points to, return a
//      pointer to the one of those other robots with the least amount
//      of energy remaining (if there's a tie, any one of the tied robots
//      will do); otherwise, return NULL.
//
	{

	}

bool Valley::energySourceAt(int r, int c) const
{
  for (int k = 0; k < m_nsources; k++)
  {
      if ((m_sources[k]->row()== r) 
       && (m_sources[k]->col()== c))
            return true;
  }
  return false;
}