有如下程序: #include<iostream> using namespace std; class ONE { public:virtual void f() { cout << "1"; } }; class TWO: public ONE { public:TWO() {cout << "2"; } }; class THREE: public TWO { public:virtual void f() { TWO::f(); cout << "3"; } }; int main() { ONE aa, *p; TWO bb; THREE cc; p = &cc; P->f(); return 0; } 执行上面程序的输出是 【11】