Множественное наследование

//
//  VirtualInheritance - using virtual inheritance the
//             Bed and Sofa classes can share a common base
//
#include <cstdio>
#include <cstdlib>
#include <iostream>
using namespace std;
 
// Furniture - more fundamental concept; this class
//             has "weight" as a property
class Furniture
{
  public:
    Furniture(int w = 0) : weight(w) {}
    int weight;
};
 
class Bed : virtual public Furniture
{
  public:
    Bed() {}
    void sleep(){ cout << "Sleep" << endl; }
};
 
class Sofa : virtual public Furniture
{
  public:
    Sofa(){}
    void watchTV(){ cout << "Watch TV" << endl; }
};
 
// SleeperSofa - is both a Bed and a Sofa
class SleeperSofa : public Bed, public Sofa
{
  public:
    SleeperSofa(int weight) : Furniture(weight) {}
    void foldOut(){ cout << "Fold out" << endl; }
};
 
int main(int nNumberofArgs, char* pszArgs[])
{
    SleeperSofa ss(10);
    
    // Section 1 -
    // the following is no longer ambiguous;
    // there's only one weight shared between Sofa and Bed
    // Furniture::Sofa or a Furniture::Bed?
    cout << "Weight = "
         << ss.weight
         << ss.foldOut()
         << endl;
 
    // Section 2 -
    // the following specifies the inheritance path
    // unambiguously - sort of ruins the effect
    SleeperSofa* pSS = &ss;
    Sofa* pSofa = (Sofa*)pSS;
    Furniture* pFurniture = (Furniture*)pSofa;
    cout << "Weight = "
         << pFurniture->weight
         << endl;
 
    // wait until user is ready before terminating program
    // to allow the user to see the program results
    system("PAUSE");
    return 0;
}

   cout << "Weight = "
         << ss.weight
         << ss.foldOut()
         << endl;

   cout << "Weight = "
         << ss.weight
         << endl;
        ss.foldOut()

//
//  VirtualInheritance - using virtual inheritance the
//             Bed and Sofa classes can share a common base
//
#include <cstdio>
#include <cstdlib>
#include <iostream>
using namespace std;
 
// Furniture - more fundamental concept; this class
//             has "weight" as a property
class Furniture
{
  public:
    Furniture(int w = 0) : weight(w) {}
    int weight;
};
 
class Bed : virtual public Furniture
{
  public:
    Bed() {}
    void sleep(){ cout << "Sleep" << endl; }
};
 
class Sofa : virtual public Furniture
{
  public:
    Sofa(){}
    void watchTV(){ cout << "Watch TV" << endl; }
};
 
// SleeperSofa - is both a Bed and a Sofa
class SleeperSofa : public Bed, public Sofa
{
  public:
    SleeperSofa(int weight) : Furniture(weight) {}
    void foldOut(){ cout << "Fold out" << endl; }
};
 
int main(int nNumberofArgs, char* pszArgs[])
{
    SleeperSofa ss(10);
    
    // Section 1 -
    // the following is no longer ambiguous;
    // there's only one weight shared between Sofa and Bed
    // Furniture::Sofa or a Furniture::Bed?
    cout << "Weight = "
         << ss.weight<<endl;
         ss.foldOut(); // ТУТ ВЫЗЫВАЕМ ФУНКЦИЮ
 
    // Section 2 -
    // the following specifies the inheritance path
    // unambiguously - sort of ruins the effect
    SleeperSofa* pSS = &ss;
    Sofa* pSofa = (Sofa*)pSS;
    Furniture* pFurniture = (Furniture*)pSofa;
    cout << "Weight = "
         << pFurniture->weight
         << endl;
 
    // wait until user is ready before terminating program
    // to allow the user to see the program results
    system("PAUSE");
    return 0;
}