Cpp questions

Hi
A windows api program which only register windows class (oop) and all other code is choice of coding c style without use subclass
Still counts as cpp?
Subclass mostly used messages better and more correct cpp coding style vs very big wndproc?
What supposed to be normal. Exe file size output in cpp?
20+kb without big. Ico files?
Compiler Optimisation settings? Enable full program optimize option do anything useful
Switch to other compiler?
Separate threads calling gdi better or not?

Can you post some of your code?