If it's a specific member, you simply just test that specific member you want to test (i.e. x or y).
If it's either number, you can test them both and OR them together.
If it's both, you can just test both and AND them together.
Why do you need to do this?
If it's to see if it's outside of a certain area, it might make more semantic sense (and possibly less code) to see if it's inside an
sf::Rect instead.