“using namespace” in c++ headers

Question

In all our c++ courses, all the teachers always put using namespace std; right after the #includes in their .h files. This seems to me

Answer 1

Check out the Goddard Space Flight Center coding standards (for C and C++). That turns out to be a bit harder than it used to be - see the updated answers to the SO questions:

• Should I use #include in headers
• Self-sufficient headers in C and C++

The GSFC C++ coding standard says:

§3.3.7 Each header file shall #include the files it needs to compile, rather than forcing users to #include the needed files. #includes shall be limited to what the header needs; other #includes should be placed in the source file.

The first of the cross-referenced questions now includes a quote from the GSFC C coding standard, and the rationale, but the substance ends up being the same.