double sqr(double x)
{
  return x*x;
}

long foo(double x[], double y[], double ThisX, double ThisY, double CloseDist, double *ThisDistp)
{
  long j=0;
  double ThisDist;
  do {
    ThisDist = sqr(x[j]-ThisX); //+sqr(y[j]-ThisY);
    j++;
  } while (ThisDist > CloseDist);
  *ThisDistp = ThisDist;
  return j;
}