Basically once you've put a using namespace std; in your header, and someone has included your header, there's no way to undo the using. This can reduce your options when a name conflict occurs.

Course.h This header file defines the Course class, representing courses offered in the system. Here are the details: Class Definition: Course: Represents a course in the system. Attributes: Various ...

Statements are executable and can have breakpoints set on them. Everything else can't.* Really the non-executable stuff in a header is no different than the non-executable stuff in a source file.