Re: inheritance - method resolution

From:

Pete Becker <pete@versatilecoding.com>

Newsgroups:

comp.lang.c++

Date:

Thu, 7 Apr 2011 15:08:20 -0400

Message-ID:

<2011040715082023772-pete@versatilecodingcom>

On 2011-04-07 13:12:10 -0400, Christopher said:

Where is the rule that explains why this will not compile? I've always
expected this to work, but it would appear that I haven't run into
this problem yet.

To resolve the problem, do I really need to override every single
method from the Base with the same name as the specific method I am
interested in overriding? I have a good 20 of them in production code.

A simple test case to reproduce what I am experiencing in more
complicated code:

class Base
{
public:
   virtual void Foo()
   {
   }

   void Foo(int x)
   {

   }
};

class Derived : public Base
{
public:
   void Foo()
   {
   }
};

int main()
{

   Derived * blah = new Derived();
   blah->Foo(5);
   delete blah;

   return 0;
}

Overloading applies to names defined in the same scope. Base defines
two versions of Foo, so when you have an object of type Base you can
use overloading to select which function to call. Derived, however,
defines one version of Foo, so there's nothing to overload. As others
have said, adding a using directive in Derived tells the compiler to
pretend that all of the Foos defined in Base were also defined in
Derived; now you have two versions of Foo in Derived, and you can use
overloading to pick the one to call.

--
Pete
Roundhouse Consulting, Ltd. (www.versatilecoding.com) Author of "The
Standard C++ Library Extensions: a Tutorial and Reference
(www.petebecker.com/tr1book)