The following code example is taken from the book
C++ Templates - The Complete Guide, 2nd Edition
by David Vandevoorde, Nicolai M. Josuttis, and Douglas Gregor,
Addison-Wesley, 2017
© Copyright David Vandevoorde, Nicolai M. Josuttis, Douglas Gregor 2017
#ifndef MYFIRST_HPP
#define MYFIRST_HPP
// declaration of template
template<typename T>
void printTypeof (T const&);
#endif // MYFIRST_HPP