C++棱形继承

#include<iostream>
using namespace std;
class animal //定义animal类
{
    
    
public:
int M_age;};
class wolf :virtual public animal {
    
    };
class dog :virtual public animal {
    
    };//继承animal类
class demiwolf:public wolf,dog{
    
    };//继承wolf,dog类
int main()
{
    
    
demiwolf a;
a.wolf::M_age = 28;
a.M_age = 18;
cout << "a.wolf::M_age=" << a.wolf::M_age << endl;
cout << "a.M_age =" << a.M_age  << endl;
return 0;
}