若有以下程序: include <iostream> using namespace std; class Base { public: void who() { cout<<'class Base'<<end1; } }; class Derivedl : public Base { public: void who() { cout<<'class Derivedl'<<end1; } }; class Derived2 : public Base { public: void who() { cout<<'class Derived2'<<end1; } }; int main() { Base *p; Derivedl obj1; Derived2 obi2; p=&obj 1; p=&obj2; p->who ( ); return 0; } 则该程序运行后的输出结果是【 】。