Header Files - Review
Declare in the header file any function accessible from another file that has a function prototype
Declare in the header file any global variables accessible by a client. Use the extern modifier (when the variable is defined in another source file)
do not put a definition - a declaration that allocates space - in a header file
Include any #define constants to be used by the client in the header file
Put macros to be used by the client in the header file
Include data structure and typedef declarations used by the client in the header file