What should go into an .h file?

Question

When dividing your code up into multiple files just what exactly should go into an .h file and what should go into a .cpp file?

Answer 1

I'd expect to see:

• declarations
• comments
• definitions marked inline
• templates

the really answer though is what not to put in:

• definitons (can lead to things being multiply defined)
• using declarations/directives (forces them on anyone including your header, can cause nameclashes)