C++第07课 继承 （三）

class A {
public:
    A(int a) :a(a) {}
    int a;
};

class B :virtual public A{
public:
    B(int a, int b) :A(a), b(b) {}
    int b;
};
class C :virtual public A {
public:
    C(int a, int c) :A(a), c(c) {}
    int c;
};
class D:public B,public  C {
public:
    //虚继承导致子类必须调用祖父类的构造函数
    D() :B(1,2),C(10,20),A(100) {}
    void print()
    {
        cout << a << endl;        //100
        cout << B::a << endl;    //100
        cout << C::a << endl;    //100
    }
};

int main()
{
    D d;
    d.print();
    return 0;
}