#include <IOSTREAM.H>

 //基类

 class CBase

 ...{

 protected:

     int a;

 public:

     CBase(int na)

     ...{

         a=na;

         cout<<"CBase constructor! ";

     }  

     ~CBase()...{cout<<"CBase deconstructor! ";}

 };  

 //派生类1(声明CBase为虚基类)

 class CDerive1:virtual public CBase

 ...{

 public:

     CDerive1(int na):CBase(na)

     ...{

         cout<<"CDerive1 constructor! ";

     }  

     ~CDerive1()...{cout<<"CDerive1 deconstructor! ";}  

     int GetA()...{return a;}

 };  

 //派生类2(声明CBase为虚基类)

 class CDerive2:virtual public CBase

 ...{

 public:

     CDerive2(int na):CBase(na)

     ...{

         cout<<"CDerive2 constructor! ";

     }

     ~CDerive2()...{cout<<"CDerive2 deconstructor! ";}

     int GetA()...{return a;}

 };  

 //子派生类

 class CDerive12:public CDerive1,public CDerive2

 ...{

 public:

     CDerive12(int na1,int na2,int na3):CDerive1(na1),CDerive2(na2),CBase(na3)

     ...{

         cout<<"CDerive12 constructor! ";

     }

     ~CDerive12()...{cout<<"CDerive12 deconstructor! ";}

 };

 void main()

 ...{

     CDerive12 obj(,,);

     //得到从CDerive1继承的值

     cout<<" from CDerive1 : a = "<<obj.CDerive1::GetA();

     //得到从CDerive2继承的值

     cout<<" from CDerive2 : a = "<<obj.CDerive2::GetA()<<endl<<endl;

 }