I have a *large* C++ program, programmed very basically without a lot of C++ experience. Now I want to make it more modular. I am thinking kind of "plug-in" like. There are various algorithms and sequences that I want to easily turn on or off when I run the program (can be just by uncommenting/commenting a certain function call). I want to be able to define all my variables in one header file (as I now have it), and use these variables in the "plug-in" or "module" or what ever I should use.
Sorry for the bad sjargon, I do not know where to start searching for what I need.