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mot。rcar类和bicycle类。然后以mottorcar和bicycle作为基类,再派生出motorcycle类。要求将vehicle作为虚

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问题 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mot。rcar类和bicycle类。然后以mottorcar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(intmaxspeed,intweight):_______
~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**********
classmotorcycle:______________
{
public:
motorcycle(int maxspeed,int weight,int height):vehicle(maxspeed,weight),bicycle(maxspeed,weight,height),motorcar(maxspeed,weight,1){}
};
void main()
{
motorcycle a(80,150,10);
cout<<a.getMaxSpeed()<<endl;
cout<<a.getWeight()<<endl;
cout<<a.getHeight()<<endl;
cout<<a.getSeatNum()<<endl;
}

选项

答案(1)MaxSpeed(maxspeed),Weight(weight){}; (2)virtual (3)virtual (4)public bicycle,public motorcar

解析 本题考查vehicle类及其派生类motorcar和bicvcle,再由这两类派生出motorcycle类,其中涉及构造函数、成员函数和析构函数。构造函数采用成员初始化列表来完成对私有成员的初始化,派生类的书写要注意关键字。
(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。
虚基类继承时要添加关键字virtual,以避免二义性。
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