c++ - Use of "using namespace" when declaring that namespace -

c++ - Use of "using namespace" when declaring that namespace -

suppose have next files:

// someclass.h namespace illustration { class someclass { ... someclass somefunction(); ... }; } // someclass.cpp example::someclass example::someclass::somefunction() { ... }

would there consequences add together "using namespace example;" before namespace in someclass.h eliminate need of adding "example::" scope operator things in someclass.cpp file? if there no conesequences, considered bad coding practice?

the alter follows:

// someclass.h using namespace example; namespace illustration { class someclass { ... someclass somefunction(); ... }; } // someclass.cpp someclass someclass::somefunction() { ... }

no, please don't set using namespace ...; in global area. can this:

someclass.h

// using namespace example; // never here please namespace illustration { using namespace otherexample; // okay (not global) class someclass { ... someclass somefunction(); ... }; }

someclass.cpp

namespace illustration // same in .h { using namespace otherexample; // okay (not global) someclass someclass::somefunction() { ... } }

and suggest potentially huge namespaces std:: never utilize using namespace std; within own namespaces because drag in many mutual symbol names.

c++ namespaces coding-style