cppreference.com > C/C++ Keywords > using using The using keyword is used to import a namespace (or parts of a namespace) into the current scope. Example code: For example, the following code imports the entire std namespace into the current scope so that items within that namespace can be used without a preceeding "std::".
     using namespace std;
Alternatively, the next code snippet just imports a single element of the std namespace into the current namespace:
     using std::cout;
Related topics: namespace