void fileMinMax(double* pMin, double* pMax)
{
  ifstream fin("data.txt");

  char c;
  fin >> c >> c;

  int n;
  fin >> n; 
  
  for(int i=0; i < n; i++)
  {
    // read a number from the file 
    double x;
    fin >> x;

    if( i == 0 ) // the first time
    {
      *pMax = *pMin = x;    // dereference! 
    }
    else // second time or later
    {
      if( *pMin > x ) // do we have to update the minimum? 
        *pMin = x;
      
      if( *pMax < x ) // do we have to update the maximum?
        *pMax = x;
    }
  }
}