Re: Abstract classes, multiple inheritance, and implemention question

From:

"Igor Tandetnik" <itandetnik@mvps.org>

Newsgroups:

microsoft.public.vc.language

Date:

Sat, 21 Jun 2008 18:13:22 -0400

Message-ID:

<OFLFLw#0IHA.5564@TK2MSFTNGP06.phx.gbl>

"Bogdan" <bogdan@company.com> wrote in message
news:%23PhXpM70IHA.4164@TK2MSFTNGP03.phx.gbl

I have 2 abstract structs as follows:

struct s1 {
   virtual void f1() = 0;
   virtual void f2() = 0;
};

struct s2 : public s1{
   virtual void f3() = 0;
};

I also have 2 implementation classes:

class s1imp : pubic s1 {
   virtual void f1() {}
   virtual void f2() {}
};

class s2imp : public s2 {
  virtual void f1() {}
  virtual void f2() {}
  virtual void f3() {}
};

Is there a way for class s2imp to derive from s1imp to take advantage
of its implementation of s1 (i.e. f1() and f2()) and provide the
implementation of f3() only?

template <typename Itf>
class s1imp_t : public Itf {
   virtual void f1() {}
   virtual void f2() {}
};

class s1imp : public s1imp_t<s1> {};
class s2imp : public s1imp_t<s2> {
    virtual void f3() {}
};

--
With best wishes,
    Igor Tandetnik

With sufficient thrust, pigs fly just fine. However, this is not
necessarily a good idea. It is hard to be sure where they are going to
land, and it could be dangerous sitting under them as they fly
overhead. -- RFC 1925