The using directive
Here is what one online resource has to say about the using directive:
"All the elements of the standard C++ library are declared within what is called a namespace, the namespace with the name std. So in order to access its functionality we declare with this expression that we will be using these entities."
This may not mean anything to you at this point.
For now you will simply have to remember to follow this format for the programs that you write for the lab projects for this course.