c++ 虚继承

class A
{
        char k[3];
        public:
                virtual void aa(){};
};

class B:public virtual A
{
        char k[3];
        public:
                virtual void bb(){};
};
class C :public virtual B
{
        char k[3];
        public:
                virtual void cc(){};
};

class D:public virtual A
{
        //char k[3];

        public:
        //      void dd(){};

};

void test()
{
        cout<<"sizeof(A)="<<sizeof(A)<<endl;
        cout<<"sizeof(B)="<<sizeof(B)<<endl;
        cout<<"sizeof(C)="<<sizeof(C)<<endl;
        cout<<"sizeof(D)="<<sizeof(D)<<endl;
}