Okay, I think (not entirely sure) that the way people are able to change in-program features (such as hacking a game or website), they need to find an address of a variable, and they need to change the variable to allow them to use a feature that they would normally not be able to use...?

I guess, and correct me if I'm wrong, they could enter in the amount of money their character has by changing the variable that accounts for his player's money.

So, I suppose I could change the address using the

WriteProcessMemory

Function, but how do I find the address of the feature, and how can I keep other people from finding this address?

Question me if you don't understand my query, I am a little confused at the moment, and thank you for any help.

you can find the address by using memory-scanning tools
Cheat Engine (http://cheatengine.org/) is a popular one

as for code protection, that's an entirely separate topic altogether & one i'm far from qualified to speak about

Thanks for the cheatengine program ^_^

Now, I just need to know how to prevent this =P