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
struct Person {
std::string firstName;
std::string lastName;
friend std::ostream& operator<<(std::ostream& strm, Person const& p) {
return strm << p.lastName << ", " << p.firstName;
}
};