执行如下程序将输出():#include＜iostream＞using namespace std;classBase{public: Base(){cout＜＜"BB";fun();}void fun (){tout＜＜"Brim";}};classDerived:publicBase{public: Derived(){cout＜＜"DD";}void fun (){cout＜＜"Dfun";}};int main(){Derived d;return 0;}