问答题
请使用VC6或使用【答题】菜单打开考生文件夹proj2下的工程proj2,其中定义了vehicle类,并派生出motorcar类和bicycle类。然后以motorcar和bicycle作为基类,再派生出motorcycle类。要求将vehicle作为虚基类,避免二叉性问题。请在程序中的横线处填写适当的代码并删除横线,以实现上述类定义。此程序的正确输出结果应为: 80 150 100 l 注意:只能在横线处填写适当的代码,不要改动程序中的其他内容,也不要删除或移动“//****found****”。 #include<iostream.h> class vehicle { private: int MaxSpeed; int Weight public: //**********found********** vehicle(int maxspeed,int weight):_________ ~vehicle(){}; int getMaxSpeed(){return MaxSpeed;} int getWeight(){return Weight;} }; //**********found********** class bicycle:_________public vehicle { private: int Height; public: bicycle(int maxspeed,int weight,int height):vehicle(maxspeed,weight),Height(height){} int getHeight(){return Height;}; }; //**********found********** class motorcar:__________public vehicle { private: int SeatNum; public: motorcar(int maxspeed,int weight,int seatnum):vehicle(maxspeed,weight),SeatNum(seatnum){} int getSeatNum(){return SeatNum;}; }; //**********found********** class motorcycle:__________ { public: motorcycle(int maxspeed,int weight,int height):vehicle(maxspeed,weight),bicycle(maxspeed,weight,height),motorcar(maxspeed,weight,1){} }; void main() { motorcycle a(80,150,100); cout<<a.getMaxSpeed()<<endl; cout<<a.getWeight()<<endl; cout<<a.getHeight()<<endl; cout<<a.getSeatNum()<<endl; }
【正确答案】正确答案:(1)MaxSpeed(maxspeed),Weight(weight){}; (2)virtual (3)virtual (4)public bicycle,public motorcar
【答案解析】解析:(1)主要考查考生对构造函数的掌握,构造函数使用初始化列表来对私有成员MaxSpeed和Weight初始化。 (2)主要考查考生对派生类的掌握,题目要求将vehicle作为虚基类,避免二义性问题。因此在这里添加virtual使vehicle成为虚基类。 (3)主要考查考生对派生类的掌握,题目要求以motorcar和bicycle作为基类,再派生出motorcycle类。在主函数中可以看到motorcycle类的实例a调用getH。sight函数和getSeatNum函数,由此可知这两个基类都是公有继承,因此得出语句:public bicycle,public motorcar。