Re: C++ boxing

Is there a way to box a type in c++ like this:

class Interface
{
public:
    virtual void foo() = 0;

};

class A
{
public:
    void foo();

};

And then I could box this type like this:
Interface * a = box_cast<Interface*>(new A());

perhaps,
class B : public A, public virtual Interface
{

};

Maybe this is called something else in C++, because everytime i google
c++ boxing it refers me to .Net boxing, which is a similiar since a
struct in c# that has an interface isnt polymorphic, so it boxes the
type, essentially creating a new type that inherits that interface. Is
there a way to do something similiar in standard c++?