Exceptional C++ Style 40 New Engineering Puzzles, Programming Problems, and Solutions

Chapter 16. (Mostly) Private

Difficulty: 5

In C++, to what extent are the private parts of a class really truly private? In this Item, we see how private names are definitely not accessible from outside nonfriend code, and yet they do leak out of a class in small ways—some of which are well known, others of which aren't, and one of which can even be done as a coldly calculated, deliberate act.

Guru Question

1. Quick—assuming that the Twice functions are defined in another translation unit that is included in the link, should the following C++ program compile and run correctly? If no, why not? If yes, what is the output?

   // Twice(x) returns 2*x
   // class Calc { public: double Twice(double d); private: int Twice(int i); std::complex<float> Twice(std::complex<float> ...