面向?qū)ο驝++習(xí)題參考解答

1、4-8 定義一個(gè)Dog類，包含age,weight等屬性，以及對這些屬性操作的方法。實(shí)現(xiàn)并測試這個(gè)類。#include using namespace std;class Dogpublic:void setAge(int a)age=a;int getAge()return age;void setWeight(float w)weight=w;float getWeight()return weight;private:int age;float weight;void main()Dog d;d.setAge(3);d.setWeight(30);cout小狗：d.getAge()歲，重

2、d.getWeight()斤。endl;4-9 設(shè)計(jì)并測試一個(gè)名為Rectangle的矩形類，其屬性為矩形的左下角與右上角兩個(gè)點(diǎn)的坐標(biāo)，根據(jù)坐標(biāo)能計(jì)算矩形的面積。#include #include using namespace std;class Rectanglepublic:Rectangle(int xx1,int yy1,int xx2,int yy2)x1=xx1;y1=yy1;x2=xx2;y2=yy2;float getArea()return fabs(x2-x1)*fabs(y2-y1);private:int x1,y1;int x2,y2;void main()Rect

3、angle rec(0,0,10,20);cout矩形面積：rec.getArea()endl;4-11 定義并實(shí)現(xiàn)一個(gè)矩形類，有長、寬兩個(gè)屬性，由成員函數(shù)計(jì)算矩形的面積。#include using namespace std;class Rectanglepublic:Rectangle(int l,int w)length=l;width=w;float getArea()return length*width;private:int length;int width;void main()Rectangle rec(10,20);cout矩形面積：rec.getArea()endl;4

4、-13 定義一個(gè)Circle類，有數(shù)據(jù)成員radius（半徑），成員函數(shù)getArea()，計(jì)算圓的面積，構(gòu)造一個(gè)Circle的對象進(jìn)行測試。#include using namespace std;const float PI=3.1415;class Circlepublic:Circle(float r)radius=r;float getArea()return radius*PI*PI;private:float radius;void main()Circle c(5.5);cout圓的面積：c.getArea()endl;4-20 定義一個(gè)復(fù)數(shù)類Complex，使得下面的代碼能夠

5、工作。Complex c1(3,5);Complex c2=4.5;c1.add(c2);c1.show();/源程序如下：#include using namespace std;class Complexpublic:Complex(float r=0.0,float i=0.0)real=r;image=i;void add(Complex b)real=real+b.real;image=image+b.image;void show()coutreal+imageiendl;private:float real; /實(shí)部float image; /虛部;void main()Comp

6、lex c1(3,5);Complex c2=4.5; /相當(dāng)于Complex c2(4.5);c1.add(c2);c1.show();5-7 定義一個(gè)Cat類，擁有靜態(tài)數(shù)據(jù)成員numOfCats,記錄Cat的個(gè)體數(shù)目；靜態(tài)成員函數(shù)getNumOfCats()，讀取numOfCats。設(shè)計(jì)程序測試這個(gè)類，體會靜態(tài)數(shù)據(jù)成員和靜態(tài)成員函數(shù)的用法。#include using namespace std;class Catpublic:Cat()numOfCats+;Cat()numOfCats-;static int getNumOfCats()return numOfCats;private:

7、static int numOfCats;int Cat:numOfCats=0;void main()cout現(xiàn)在的Cat數(shù)量：Cat:getNumOfCats()endl;Cat a;cout現(xiàn)在的Cat數(shù)量：a.getNumOfCats()endl;Cat b;cout現(xiàn)在的Cat數(shù)量：b.getNumOfCats()endl;5-14 定義Boat與Car兩個(gè)類，二者都有weight屬性，定義二者的一個(gè)友元函數(shù)getTotalWeight()，計(jì)算二者的重量和。#include using namespace std;class Car;class Boatpublic:Boat(fl

8、oat w)weight=w;friend float getTotalWeight(Boat b,Car c);private:float weight;class Carpublic:Car(float w)weight=w;friend float getTotalWeight(Boat b,Car c);private:float weight;float getTotalWeight(Boat b,Car c)return b.weight+c.weight;void main()Boat boat(3500);Car car(1000);cout船和汽車共重getTotalWeig

9、ht(boat,car)公斤。endl;7-5 定義一個(gè)基類Shape，在此基礎(chǔ)上派生出Rectangle和Circle，二者都有g(shù)etArea()函數(shù)計(jì)算對象的面積。使用Rectangle類創(chuàng)建一個(gè)派生類Square。#include using namespace std;const float PI=3.14;class Shapepublic:Shape(float a,float b=0.0)this-a=a;this-b=b;protected:float a,b;class Rectangle : public Shapepublic:Rectangle(float l,floa

10、t w):Shape(l,w)float getArea()return a*b;class Circle : public Shapepublic:Circle(float r):Shape(r)float getArea()return a*PI*PI;class Square : public Rectanglepublic:Square(float l):Rectangle(l,l)float getArea()return a*a;void main()Rectangle r(10,20);Circle c(5);Square s(10);cout矩形的面積：r.getArea()e

11、ndl;cout圓的面積：c.getArea()endl;cout正方形的面積：s.getArea()endl;7-6 定義一個(gè)哺乳動物類Mammal，再由此派生出狗類Dog，定義一個(gè)Dog類的對象，觀察基類與派生類的構(gòu)造函數(shù)和析構(gòu)函數(shù)的調(diào)用順序。#include using namespace std;class Mammalpublic:Mammal()coutConstructing Mammal.endl;Mammal()coutDesstructing Mammal.endl;class Dog : public Mammalpublic:Dog()coutConstructing

12、Dog.endl;Dog()coutDesstructing Dog.endl;void main()Dog d;7-8 定義一個(gè)Document類，有數(shù)據(jù)成員name，從Document派生出Book類，增加數(shù)據(jù)成員pageCount。#include using namespace std;class Documentpublic:Document(char * n)strcpy(name,n);void show()coutname;private:char name50;class Book : public Documentpublic:Book(char *n,int p):Doc

13、ument(n),pageCount(p)void show()cout書名：;Document:show();coutendl頁數(shù)：pageCountendl;private:int pageCount;void main()Book book(C+語言程序設(shè)計(jì),529);book.show();7-10 定義一個(gè)Object類，有數(shù)據(jù)成員weight及相應(yīng)的操作函數(shù)，由此派生出Box類，增加數(shù)據(jù)成員height和width及相應(yīng)的操作函數(shù)，聲明一個(gè)Box對象，觀察構(gòu)造函數(shù)與析構(gòu)函數(shù)的調(diào)用順序。#include using namespace std;class Objectpublic:O

14、bject()coutConstructing Object.endl;Object()coutDestructing Object.endl;void setWeight(int w)weight=w;int getWeight()return weight;private:int weight;class Box : public Objectpublic:Box()coutConstructing Box.endl;Box()coutDestructing Box.endl;void setHeight(int h)height=h;int getHeight()return heigh

15、t;void setWidth(int w)width=w;int getWidth()return width;private:int height;int width;void main()Box box;box.setHeight(5);box.setWidth(10);box.setWeight(8);cout盒子：高box.getHeight()，寬box.getWidth()，重box.getWeight()endl;8-4#include using namespace std;class Counterpublic:Counter(int ii=0)i=ii;void prin

16、t()couti=iendl;Counter operator +(int a)Counter temp;temp.i=i+a;return temp;private:int i;void main()Counter c;c=c+3;c.print();c=c+5;c.print();8-5#include using namespace std;class Mammalpublic:virtual void speak()coutMammal Speak!endl;class Dog:public Mammalpublic:virtual void speak()coutDog Speak!speak();8-7#include using