Calling functions in Pure virtual class

[caperover2002]

Hi, Lindley,

Thanks for your quick reply.

foo(a, b) is also a pure virtual function, which will be defined later in another class, say, E. If I explicilty tell D to call B::foo, will it invoke E:foo(a, b) in the end, or complain that B:foo(a,b) is pure virtual?

As I understand, what "using B::foo" really does is to embed B:foo in the scope of D. If so, will it be equivalent to repeating declaring foo(int a,int b) in D even if it is pure virtual?

Thanks,
CR

The compiler stops searching the base class for a method called foo() when it sees one in the derived class, unless you explicitly tell it to do so:

class D : public B
{
public:
    using B::foo;
    virtual double foo(int a)
    {
        doube c = foo(a, 1.0);
        return c;
    }
}

Note, in this limited example this still won't compile, since it will say that D is an abstract class since nothing in the hierarchy provides a concrete implementation of foo(int,int) which is pure virtual.