Managing multiple C++ files in one project

Hello, I am working on a project that I feel will be rather big, so instead of having all my code in one huge cpp file I wish to split the cpp files so that one cpp file handles one set of functions, and another cpp file handles another set of functions.

I really am clueless how to do this. When I tried at first to add cpp files, then I get the error message that some of my global variables have not been declared.

What is the best and most organized way of solving my problem? Any help will be appreciated.

Thanks.

'extern' all your variables in all other cpp files, except the one they are declared in.

eg,

extern int cnt;
extern char mychar;

This is to tell the compiler that those variables have been declared elsewhere but not in this cpp file(external to this file)

Or better yet, extern them in a common header file.

I would just like to sincerely thank you guys for answering my question in a simple manner.

I got it to work exactly how I wanted it to and now I can easily go back and forth between different sections of code.