单项选择题
下列程序的输出结果是( )。#include using namespace std;class Base{public: virtual void display() { cout << "B" << endl;}};class Derived: public Base {public: void display() { cout << "D" << endl;}};void f( Base *p){ p->display();}int main(){ Derived d; f(&d); return 0;}
A、B
B、BD
C、D
D、DB