Should C++ 'interfaces' have a virtual destructor [duplicate]

Answer 1

You should always use a virtual destructor with interfaces. Case in point:

IAnimal* animal = new Lion();
delete animal;

Now what destructor is it going to use? Definately not the Lion's destructor because the interface doesn't know about Lion's destructor.

So, have this if your interface has no memory management:

virtual ~IAnimal(){}