以下程序的执行结果为 【8】 。 #include<iostream> using namespace std; class base {public: virtual void who( ){ cout<<"base class"<<endl;} }; class derivel:public base {public: void who( ) { cout<<"derivel class"<<endl; }}; class derive2:public base {public: void who( ){ cout<<"derive2 class"<<endl;} }; void main( ) {base objl,*p;derivel obj2;derive2 obj3;P=&objl;p->who( );p=&obj2;p->who( );p=&obj3;p->who( ); }