Private inheritance

[gionna]

What do you need a private access writer if all base class fields are inaccessible?

[emran]

It is in order that all members of the base class are not available outside ( only available from the interior of the class or from friends of the class).

The inheritance is not much different from the aggregation, and
class A : private B { ... }; similar
class A { private: B b; };♪

Onelike private: B b;in succession B may be summoned as members of their class, i.e. not b.f()♪ f()♪

It is also possible to inherit from the abstract class and redesign its methods without showing all these cases outside, for example:

struct Callback { virtual void done() = 0; };
void run(Callback* b);
class Cls : private Callback {

public:

void some() {

run(this);

}

private:

void done() override { ... }

};