RS> #include "stdio.h"  /* I'd use , but it 
RS> doesn't really matter */

 JB> actually it makes a difference....  is in an
"include directory"
 JB> while "stdio.h" is in the current directory.

Not quite...

#include's that use double-quotes start looking in the current directory. 
Should that file not exist in the current (or, rather, source) directory,
the preprocessor treats it as if it were #include'd via angle brackets. 
This, of course, means it searches the "include path" (whatever
that may mean for your compiler - it may even include using some
environment variable!).


---