第十三周任务（1）

#include <iostream> using namespace std;class Vehicle {public: void run() const { cout << "run a vehicle. "<<endl; } //(2) run()为虚函数}; class Car: public Vehicle {public: void run() const {cout << "run a car. "<<endl; } }; class Airplane: public Vehicle {public: void run() const {cout << "run a airplane. "<<endl;} }; int main() {cout<<"(a) 直接用对象访问成员函数: "<<endl;Vehicle v;v.run();Car car; Airplane airplane; car.run();airplane.run();cout<<"(b) 用指向基类的指针访问成员函数: "<<endl;Vehicle *vp;vp=&car;vp->run();vp=&airplane;vp->run();system("pause");return 0;} 

用基类的指针访问数据成员函数时基类指针不能赋值为派生类的指针