下面程序的运算结果是( )。 #include<iostream> using namespace std; class A { public: virtual void fun()=0; }; class B:public A } public: void fun() {cout<< new file << ;} }; class C:public A { public: void fun() { cout<< open file << ;} }; void main() { A a, * p; B b;C c; p=&c; p->fun(); p=&b; }
A.new file open file
B.new file new file
C.编译出错
D.open file new file