Re: making a class

Johs wrote:


  Many people have the misconception that a header file is a file
where you dump all the type and function declarations used by a
cpp file, regardless of whether those types/functions are used
anywhere else.

  However, a header file declares the *public interface* of a module.
In other words, it declares types and functions which other modules
may need.

  As with all public interfaces, they should contain as little
implementation details as possible. (Due to technical reasons the
private sections of classes have to be declared alongside their
public sections, but that's more or less unavoidable.)

  If the implementation of a module (ie. the "cpp file") uses a
very small class, used exclusively by that module, there's often
no need to make that "public" by creating a header file for it.

  Of course if that private class is bigger it will start cluttering
the cpp file if you keep it there. If that's the case, then you might
want to put it in a separate file and make a header file for it. It
all depends on how much clutter you avoid by doing that, I suppose.

  (Sometimes, if the class is very small and all of its functions are
also very small, one option is to put the entire class, implementation
and all, in the header file, with all the functions declared inline.
This shouldn't be abused, though.)