"Vladimir Grigoriev" <vlad.moscow@mail.ru> wrote in message
news:ufzNN1oaJHA.4288@TK2MSFTNGP06.phx.gbl
"Ben Voigt [C++ MVP]" <rbv@nospam.nospam> wrote in message
news:%23bhFs8LaJHA.4684@TK2MSFTNGP03.phx.gbl...
In C++, you always get whatever behavior the base class had. Pure
virtual functions have no implementation, so then you have
interface implementation in effect.
Pure virtual functions have implementation. It is an abstract class
that has no implementation as an object. Am I wrong?
You are wrong. While pure virtual functions may, in principle, have
implementation, it is highly unusual. Most of the time, they don't.
In C++, an abstract class is a class that has at least one pure
virtual function. It can also happily have non-virtual or non-pure
member functions, complete with implementation.
Consider:
class AbstractClass {
virtual void PureVirtualNoImplementation() = 0;
virtual void PureVirtualWithImplementation() = 0;
virtual void NonPureVirtual() {}
void NonVirtual() {}
};
void AbstractClass::PureVirtualWithImplementation() {}
implementation, it is highly unusual." are two different things. So I