If you want the magic explained, here’s a start: https://en.wikipedia.org/wiki/Lempel%E2%80%93Ziv%E2%80%93Welch

Well, what problems are you trying to solve by having the classes all access each other’s data members? Why is that necessary?

Cookies required for the website to work (like that one) are totally fine and, in fact, they don’t even have to ask you about them - if they’re not used for tracking. So no, asking each time is definitely avoidable.