一到关于c＋＋继承和多态的题

 1class base
 2{
 3public:
 4        base()
 5        {
 6                cout <<" base::val "<<endl;
 7                val = 12345;
 8                print();
 9        }
        base(int x)
        {
                val = x;
                cout << " "<<endl;
        }
        virtual void print()
        {
                cout << " base:print(), val = "<<val<<endl;
        }
        base & operator = (int x)
        {
                val = x;
                cout <<" base::operator, val = "<<x<<endl;
                return *this;
        }
        void relase()
        {
                cout << " base::relase" <<endl;
        }
         ~base()
        {
                cout << " ~base::val = "<< val <<endl;
        }
protected:
        int  val;
};

class deiver:public base
{
public:
        deiver()
        {
                cout << " deiver::val "<<endl;
        }

        deiver(int x)
        {
                val = x;
                print();
        }
        void print()
        {
                cout << " deiver::print(), val =  "<< val <<endl;
        }
        void relase()
        {
                cout << " deiver::relase, val = "<<val<<endl;
        }
        deiver & operator = (int x)
        {
                val = x;
                cout <<" deiver::operator, val = "<<x<<endl;
                return *this;
        }
        ~deiver()
        {
                cout << " deiver::~deiver "<<endl;
        }
};
void des(base * b)
{
        b->print();
        b->relase();
}
deiver  de = 98765;
int main()
{
        deiver  * dee = new deiver;
        *(base *)dee = 100;
        des(dee);
        delete dee;
        return 0;
}