Question

I’m having a little problem with inheritance in C++ that I can’t quite figure out.

So, say I have some classes derived from stl list, i.e:

class Class1: public list<T>{
      virtual func1();

}

class Class2 : public Class1<w/e>{
         func1();
}

The problem I’m having is when passing these to a function. How can I properly pass an instance of one of these to a function so that it will use the proper virtual function if it is possible for an instance of either type to be passed? I haven’t done inheritance and virtual functions in awhile so I am a bit rusty here.
(This assuming that the function is not a member function of the classes).

Answer 1

You will need to pass them to the function as a reference

int function(Class1& obj);

or as a pointer;

int function(Class1* obj);

and it should just plain call the correct version of the virtual method.

If you pass them without either of those

int function(Class1 obj);

The object will be copy constructed to always be a Class1 in the function, and will always call Class1::func1()