Multiple inheritance is the the inheritance from at least two classes.

Example


#include <cassert>

#include <iostream>

#include <string>



//Abstract base class

struct State

{

  virtual const std::string ToStr() const = 0;

};



struct StateLoggedIn : public State

{

  const std::string ToStr() const { return "logged_in"; }

};



struct StateNotLoggedIn : public State

{

  const std::string ToStr() const { return "not_logged_in"; }

};





//Abstract base class

struct Administrator : public State {};



struct AdministratorLoggedIn : public Administrator, StateLoggedIn

{

  const std::string ToStr() const { return this->StateLoggedIn::ToStr(); }

};



struct AdministratorNotLoggedIn : public Administrator, StateNotLoggedIn

{

  const std::string ToStr() const { return this->StateNotLoggedIn::ToStr(); }

};





//Abstract base class

struct Participant : public State {};



struct ParticipantLoggedIn : public Participant, StateLoggedIn

{

  const std::string ToStr() const { return this->StateLoggedIn::ToStr(); }

};



struct ParticipantNotLoggedIn : public Participant, StateNotLoggedIn

{

  const std::string ToStr() const { return this->StateNotLoggedIn::ToStr(); }

};



#include <boost/scoped_ptr.hpp>

#include <boost/shared_ptr.hpp>



int main()

{



  boost::shared_ptr<Administrator> a1(new AdministratorLoggedIn);

  boost::shared_ptr<Administrator> a2(new AdministratorNotLoggedIn);

  boost::shared_ptr<Participant> p1(new ParticipantLoggedIn);

  boost::shared_ptr<Participant> p2(new ParticipantNotLoggedIn);



  assert(a1->ToStr() == p1->ToStr());

  assert(a2->ToStr() == p2->ToStr());

  std::cout << a1->ToStr() << '\n';

  std::cout << a2->ToStr() << '\n';

}

Go back to Richel Bilderbeek's C++ page.

Go back to Richel Bilderbeek's homepage.

(C++) multiple inheritance

Example