gistfile1.txt

int filtercol = ...;
int filterval = ...;
int operation = ...;
std::vector<int> pass;
for (int i = 0; i < qr.rows.size(); i++) {
  int val = qr.GetVal<int>(filtercol, i);
  switch (operation) {
  case LT:
    if (val < filterval) {
      pass.push_back(i);
    }
  case GT:
  ...

  }
}