应用题
2.请打开考生文件夹下的解决方案文件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,避免二义性问题。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
1
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() ( returnMaxSpeed;}
int getWeight() {returnWeight;}
};
//**********found**********
class bicycle:__________public
vehicle
{
private:
int Height;
public:
bicycle(int maxspeed,int weight,int height):vehicle(maxspeed, weight),Height(height){}
int getHeight(){returnHeight ;};
};
//**********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;);
};
//**********Ic found**********
class motorcycle :___________
{
public:
motorcycle(int maxspeed,int weight,int height):vehicle(maxspeed, weight),bicycle(maxspeed,weight,height),motorcar(maxspeed,weight,1){}
};
void msin()
{
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】(1)MaxSpeed(maxspeed),Weight(weight){};
(2)virtual
(3)virtual
(4)public bicycle,public motorcar
【答案解析】(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getHeight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。