c++面向对象课后答案演示教学

1、C + +面向对象课后答案第8章1.1 在C+中,三种派生方式的说明符号为public 、 private、protected不加说明,那么默认的派生方式为private.1.2 当公有派生时,基类的公有成员成为派生类的公有成员；保护成员成为派生类的保护成员；私有成员成为派生类的不能直接访问成员.当保护派生时,基类的公有成员成为派生类的 保护成员；保护成员成为派生类的保护成员；私有成员成为派生类的不能直接访问成员.1.3 派生类的构造函数一般有3项工作要完成：首先基类初始化.其次成员对象初始化,最后执行派生类构造函数体 .1.4 多继承时,多个基类中的同名的成员在派生类中由于标识符不唯一而出现

2、二义性.在派生类中采用 虚基类 或作用域分辨符 来消除该问题.2 .简做题2.1 派生类如何实现对基类私有成员的访问2.2 什么是类型兼容规那么2.3 派生类的构造函数是怎样的执行顺序,析构函数的执行顺序是如何实现的2.4 继承与组合之间的区别与联系是什么2.5 什么是虚基类它有什么作用含有虚基类的派生类的构造函数有什么要求,什么是最 远派生类,建立一个含有虚基类的派生类的对象时,为什么由最远派生类的构造函数负责 虚基类的初始化3 .选择题3.1 下面对派生类的描述中,错误的选项是 D .A . 一个派生类可以作为另外一个派生类的基类B.派生类至少有一个基类C.派生类的成员除了它自己的成员外,

3、还包含了它的基类的成员D.派生类中继承的基类成员的访问权限到派生类中保持不变3.2 以下对友元关系表达正确的选项是A.A.不能继承B.是类与类的关系C.是一个类的成员函数与另一个类的关系D.提升程序的运行效率3.3 当保护继承时,基类的B在派生类中成为保护成员,不能通过派生类的对象来直接 访问.A.任何成员B.公有成员和保护成员C.公有成员和私有成员D.私有成员3.4 设置虚基类的目的是B.A.简化程序B.消除二义性C.提升运行效率D.减少目标代码3.5 在公有派生情况下,有关派生类对象和基类对象的关系,不正确的表达是C .A.派生类的对象可以赋给基类的对象B.派生类的对象可以初始化基类的引用

4、C.派生类的对象可以直接访问基类中的成员D.派生类的对象的地址可以赋给指向基类的指针3.6 有如下类定义：class MyBASE int k;public:void set(int n) k=n; int get( ) const return k; ；class MyDERIVED: protected MyBASE protected;int j;public:void set(int m,int n)MyBASE:set(m);j=n; int get( ) constreturn MyBASE:get( )+j; ;那么类MyDERIVED中保护成员个数是(B).A. 4 B. 3

5、C. 2 D. 13.7 程序如下：#include<iostream> using namespace std;class A public:A( ) cout<< " A" ；;class B public:B( ) cout<< " B" ; ;class C: public AB b;public:C( ) cout<< " C" ；;int main( ) C obj; return 0;执行后的输出结果是(D).A. CBA B . BAC C . ACB D . ABC3.

6、8 类O定义了私有函数F1.P和Q为O的派生类,定义为 class P: protected O;class Q: public O.(C)可以访问 Fl.A. O的对象 B. P类内 C. O类内 D. Q类内3.9 有如下类定义：class XAint x;public:XA(int n) x=n; ;class XB: public XA int y;public:XB(int a,int b);在构造函数XB的以下定义中,正确的选项是B.A . XB:XB (int a, B. XB:XB (int a, C. XB:XB (int a, D . XB:XB (int a, 3.10有

7、如下程序： #include<iostream> using namespace std; class Base private:void fun1( ) const cout<< protected:void fun2( ) const cout<< public:void fun3( ) const cout<<int b) : x(a), y(b) int b) : XA(a) , y(b) int b) : x(a), XB(b) int b) : XA(a) , XB(b) funl ;fun2" ;fun3" ;c

8、lass Derived : protected Basepublic:void fun4( ) const cout<< " fun4" ;int main()Derived obj;obj.fun1( ); / obj.fun2( ); / obj.fun3(); / obj.fun4( ); / 其中没有语法错误的语句是(D ).A. B.C.D.4.写出程序运行结果4.l#include<iostream>using namespace std;class B1public:B1(int i) cout<< " cons

9、tructing B1 "<<i<<endl; B1( ) cout<< " destructing B1 "<<endl; ;class B2 public:B2( ) cout<< " constructing B3 * <<endl; B2( ) cout<< " destructing B3" <<endl; ;class C:public B2, virtual public B1 int j;public:C(int a,int

10、 b,int c):B1(a),memberB1(b) ,j(c) private:81 memberB1;82 memberB2;int main( )C obj(1,2,3);constructing B1 1constructing B3 *constructing B1 2constructing B3 *destructing B3destructing B1destructing B3destructing B14.2#include<iostream>using namespace std;class Bpublic:void f1()cout<<&quo

11、t;B:f1"<<endl;class D:public Bpublic:void f1()cout<<"D:f1"<<endl;void f(B& rb) rb.f1(); int main( ) D d;B b,&rb1=b,&rb2=d;f(rb1); f(rb2);return 0;B:f1B:f15.编程题5.1 定义一个 Point类,派生出 Rectangle类和 Circle类,计算各派生类对象的面积Area().#include<iostream> using namespa

12、ce std; const double PI=3.14159; class Point public:Point(double x=0, double y=0) X=x;Y=y;void ShowPoint() cout<<"("<< X<<","<<Y<<")"<<endl; private:double X,Y;class Rectangle: public Point public:Rectangle(double w,double h,double x,

13、double y):Point(x,y) width=w,height=h;Area(); void Area() area= width*height; void ShowArea()cout<<"Rectangle Area="<<area<<endl;private:double width,height,area;class Circle: public Point public:Circle(double r,double x, double y):Point(x,y) radius=r;Area();void Area() a

14、rea= PI*radius*radius;void ShowArea()cout<<"Circle Area="<<area<<endl;private:double radius,area;int main()Rectangle r(10,8,0,0);Circle c(4,3,5);r.ShowArea();c.ShowArea();return 0;5.2 设计一个建筑物类Building ,由它派生出教学楼Teach-Building和宿舍楼类DormBuilding ,前者包括教学楼编号、层数、教室数、总面积等根本信息,后者包

15、括宿舍楼编号、层数、宿舍数、总面积和容纳学生总人数等根本信息.#include<iostream> #include<cstring> using namespace std;enum AMPMAM=1,PM;class Buildingpublic:Building(char *);void ShowBuilding()cout<<Name;protected:char Name30;Building:Building(char *name) strcpy(Name,name);class Teach_Building: public Building p

16、ublic:Teach_Building(char *,int,int,int,int);void ShowTeach_Building()Building:ShowBuilding();cout<<" No:"<<No;cout<<" Floors:"<<Floors;cout<<" ClassRooms:"<<ClassRooms;cout<<" Area:"<<Area<<endl;protected:

17、int No,Floors,ClassRooms,Area;Teach_Building:Teach_Building(char *name,int no,int fl,int cr,int ar):Building(name) No=no;Floors=fl;ClassRooms=cr;Area=ar;class Dorm_Building:public Building public:Dorm_Building(char *,int,int,int,int,int);void ShowDorm_Building()Building:ShowBuilding();cout<<&q

18、uot; No:"<<No;cout<<" Floors:"<<Floors;cout<<" DormRooms:"<<DormRooms;cout<<" Area:"<<Area;cout<<" StudentNum:"<<StudentNum<<endl;protected:int No,Floors,DormRooms,Area,StudentNum;);Dorm_Building

19、: Dorm_Building(char *name,int no,int fl,int dr,int ar,int sn):Building(name) No=no;Floors=fl;DormRooms=dr;Area=ar;StudentNum=sn;)int main()Teach_Building tb("主教学楼",59,6,66,18000);Dorm_Building db("北苑男生宿舍,41,5,75,3750,300);tb.ShowTeach_Building();db.ShowDorm_Building(); return 0;)5.3

20、定义并描述一个 Table类和一个Circle类,由它们共同派生出 RoundTable类.(这题做得不太满意)#include<iostream> using namespace std; class Table public: Table(int legs) Legs=legs;) protected: int Legs;);class Circlepublic:Circle(int radius) Radius=radius;) protected: int Radius; );class RoundTable:public Table,public Circle publi

21、c:RoundTable(int legs,int radius):Table(legs),Circle(radius) protected: ;int main() return 0;5.4 利用第四章习题 5.2 Clock类,派生一个带“ AM、“ PM 的新时钟类 NewClock. #include<iostream>using namespace std;enum AMPMAM=1,PM;class Clockpublic:Clock(int=0, int=0, int s=0);void ShowTime()cout<<Hour<<"

22、:"<<Minute<<":"<<Second;private:int Hour,Minute,Second;Clock:Clock(int h, int m, int s)Hour=h;Minute=m;Second=s;class NewClock: public Clock public:NewClock();NewClock(Clock c,AMPM ap):Clock(c) Ap=ap;void ShowTime()Clock:ShowTime();cout<<(Ap=AM ? " AM"

23、;:" PM")<<endl; private:AMPM Ap;int main()NewClock nc(Clock(8,23,34),AMPM(2);nc.ShowTime();return 0;5.5 利用NewClock类与Date类定义一个带日期的时钟类ClockwithDate .对该类对象能进行增加减少秒数操作.#include<iostream>using namespace std;enum AMPMAM=1,PM;class Clockpublic:Clock(int=0, int=0, int s=0);void ShowTim

24、e()cout<<Hour<<":"<<Minute<<":"<<Second;protected:int Hour,Minute,Second;)；Clock:Clock(int h, int m, int s)Hour=h;Minute=m;Second=s;);class NewClock: public Clock public:NewClock(Clock c,AMPM ap):Clock(c)Ap=ap;)void ShowTime()Clock:ShowTime();cout<

25、;<(Ap=AM ? " AM": " PM")<<endl;)protected:AMPM Ap;);class Dateprotected:int Year,Month,Day;static const int days;bool LeapYear();bool EndofMonth();public:Date(int=1900,int=1,int =1);void Increment(int );void Decrement(int);void SetDate(int,int,int);void ShowDate(););cons

26、t int Date:days尸0,31,28,31,30,31,30,31,31,30,31,30,31;Date:Date(int y,int m,int d)SetDate(y,m,d);void Date:SetDate(int y,int m,int d)Year=(y>=1900 && y<=9999)?y:1900;Month=(m>=1 &&m<=12)?m:1;if(Month=2 && LeapYear()Day=(d>=1 && d<=29)?d:1;elseDay=(d&

27、gt;=1 && d<=daysMonth)?d:1;)bool Date:LeapYear()return (Year%400 = 0) | (Year%4=0 && Year%100!=0)? true:false; )bool Date二EndofMonth()if(Month=2 && LeapYear()return Day=29;elsereturn Day=daysMonth;)void Date:Increment(int n)int i;for(i=1;i<=n;i+)if(EndofMonth() &&am

28、p; Month=12)Year+; Month=Day=1;)else if(EndofMonth()Month+;Day=1;)elseDay+;)void Date:Decrement(int n)int i;for(i=1;i<=n;i+)if(Day=1)if(Month=1)Year-; Month=12; Day=31;)else if(Month=3)Day=LeapYear()?29:28;Month=2;)elseDay=days-Month;)elseDay-;)void Date:ShowDate()cout<<Year<<"-"<<Month <<"-"<<Day <<endl;)class ClockwithDate :public Date,public NewClockpublic:ClockwithDate(Date,Clock,AMPM);void IncrementSecond(int);