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
class MyClass {
private:
int value;
public:
friend bool operator < (MyClass const& x, MyClass const& y) {
return x.value < y.value;
}
friend std::ostream& operator << (std::ostream& strm, MyClass const& x) {
strm << x.value;
return strm;
}
};