Ok I have 2 classes. Class core and ball. Class ball is inheriting cores public members. But I have a problem. Both classes use each others members, so what I do? I've tried declaring ball within core but it says I cant inherit from an incomplete type. And I cant declare an instance of ball in core because ball hasn't been declared yet. I wanted to make ball a separate class for better organization because the program is over 1000 lines and it will make it easier to debug and code in.