using Directive
C++ Specific —>
usingnamespace [::] [nested-name-specifier] namespace-name
The using-directive allows the names in a namespace to be used without the namespace-name as an explicit qualifier. In contrast to a using declaration, which allows an individual name to be used without qualification, the using directive allows all the names in a namespace to be used without qualification. See using Declaration for more information.
END C++ Specific