In C++, is a function automatically virtual if it overrides a virtual function?

Question

I would expect that if foo is declared in class D, but not marked virtual, then the following code would call the implementation of foo

Answer 1

You are not creating any copy of the object of e and putting it in d. So d.foo() follows normal polymorphic behavior and calls derived class method. A method which is declared as virtual in the base class becomes automatically virtual in the derived class also.