Do most C++ programmers use composition or private inheritance?
Composition. Normally you don’t WANT to have access to the internals of too many other classes, and private inheritance gives you some of this extra power (and responsibility). But private inheritance isn’t evil; it’s just more expensive to maintain, since it increases the probability that someone will change something that will break your code. A legitimate, long-term use for private inheritance is when you want to build a class Fred that uses code in a class Wilma, and the code from class Wilma needs to invoke methods from your new class, Fred. In this case, Fred calls non-virtuals in Wilma, and Wilma calls (usually pure) virtuals in itself, which are overridden by Fred. This would be much harder to do with composition.
