Question

Right now I am using std::pair to represent a 2d point in c++. However, I am getting annoyed with having to write

typedef std::pair<double, double> Point;

Point difference = Point(p2.first - p1.first,
                         p2.second - p1.second);

instead of being able to overload operator+ and operator-.

So, my question is, to make my Point class, should I

• Publicly derive from std::pair and add my own member functions? This is nice because all my code can stay the same. I am not going to be doing anything like std::pair<double, double>* p = new Point; so I don’t have to worry about things like virtual destructors.
• Roll my own Point class, which is annoying since I am duplicating std::pair’s functionality, however I am “doing it the pure way”.
• Make template specializations of operator+ and operator- for std::pair, which admittedly I don’t remember if they go in source or header files.

I guess it’s up for debate, I’d really like to do #1 but I don’t know if it’s a bad idea since I’ve heard that inheriting from STL is a no-no.

Answer 1

You could roll your own Point class, but use std::pair internally to store the data. This prevents the inheritance from STL issue, but still uses std::pair’s functionality.