|
I know the original quote was meant as a complaint about C++, but it’s always seemed to me to be more about how people were teaching C++ in the ‘90s. What about the zinger, “if you think English is not overly complex, just what is a loud old fast tall red car, and when was the last time you needed one?” No language I’m familiar with limits the number of adjectives you can use for a single noun. That doesn’t mean you generally should string several adjectives together; usually you’re fine just saying “car,” but sometimes you need the ability to be specific. English is a complicated language, but limiting how many adjectives can apply to a particular noun would make it much worse in my opinion. As for the original question, a pure virtual function is a function that must be implemented in a derived class, while a private function is a function that can’t be accessed outside of the class, not even from derived classes. A destructor is a function used to clean up when an object goes out of scope; I don’t think anything about the destructor is important in this case, it just happens to be a convenient member function to use. The combination would make it impossible to instantiate objects of the class (because of the pure virtual function) or objects of classes that inherit from it (because the pure virtual function can’t be accessed, let alone implemented, from a derived class). That rules out much of what you’d want to do with a class. You’re left with static data and functions, and nested types. Overall, the best I can tell, you would use that to make the class imitate a namespace. But for the last twenty years, you don’t have to imitate namespaces: C++ has them. You might still find somebody trying to avoid using actual namespaces because of a vague fear of argument dependent lookup, but to be honest, I’ve never seen argument dependent lookup call the wrong function. Some programmers oppose it in principle, but in practice it doesn’t seem to cause much trouble. |