虚基类的声明

//虚基类的声明
#include<iostream>
using namespace std;
class Base{
public:
Base()
{
a=5;
cout<<"Base a="<<a<<endl;
}
protected:
int a;
};
class Base1:virtual public Base{
public:
Base1()
{
a=a+10;
cout<<"Base1 a="<<a<<endl;
}
};
class Base2:virtual public Base{
public:
Base2()
{a=a+20;
cout<<"Base2 a="<<a<<endl;}
};
class Derived:public Base1,public Base2{
public:
Derived()
{cout<<"Derived a="<<a<<endl;}
};
int main()
{
Derived obj;
return 0;
}