题目内容:
有如下程序: #include<iostream>
usingnamespacestd;
classB{
public:
virtualvoidshow(){cout<<"B";}};
classD:publicB{
public:
voidshow(){cout<<"D";}
};
voidfun1(B*ptr){ptr->show();
}voidfun2(B&ref){ref.show();
}voidfun3(BB){b.show();
}
intmain(){
Bb,*p=newD;
Dd;
funl(p);
fun2(b);
fun3(d);
return0;
}
程序的输出结果是( )。 A.BBB
B.BBD
C.DBB
D.DBD
参考答案:
答案解析: