类的作业及答案.doc

/编程：建立一个分数类。分数类的数据成员包括分子和分母，操作包括显示、输入、约分、通分、比较、加、减、乘、除、求相反数。#include#includeusing namespace std;class fractionint above; /分子int below; /分母void reduction(); /约分void makeCommond(fraction&); /通分public:fraction(int a=0,int b=1) /构造函数above=a;below=b;fraction add(fraction); /两分数相加fraction sub(fraction); /本分数减去实参分数fraction mul(fraction); /两分数相乘fraction div(fraction); /本分数除以实参分数fraction reciprocal(); /求倒数bool equal(fraction); /等于运算bool greaterThan(fraction); /大于运算bool lessThan(fraction); /小于运算void display(); /显示分数void input(); /输入分数;void fraction:reduction() /约分先求最大公约数int a,b,temp;if(below0)above=-above;below=-below;a=abs(above);b=abs(below);while(a%b) /欧几里德法求最大公约数temp=a;a=b;b=temp%b;above/=b;below/=b;void fraction:makeCommond(fraction& b)int temp;reduction();b.reduction();above*=b.below;b.above*=below;temp=below*b.below;below=b.below=temp;fraction fraction:add(fraction b)fraction temp;makeCommond(b); /通分temp.above=above+b.above;temp.below=below;temp.reduction(); /约分return temp;fraction fraction:sub(fraction b)fraction temp;makeCommond(b); /通分temp.above=above-b.above;temp.below=below;temp.reduction(); /约分return temp;fraction fraction:mul(fraction b)fraction temp;temp.above=above*b.above;temp.below=below*b.below;temp.reduction(); /约分return temp;fraction fraction:div(fraction b)fraction temp;if(b.above=0)cout零不能作除数！b.above);bool fraction:lessThan(fraction b)makeCommond(b); /通分return(aboveb.above);void fraction:display()reduction(); /约分cout为：above/belowendl;void fraction:input()while(1)cout请顺序输入分子和分母（整数）：abovebelow;if(below=0) cout分母不可为零！endl;elsereduction();return;int main()fraction f1(-3,-5),f2(-3,5),f3(3,-7),f4,f5(8);coutf1; f1.display();coutf2; f2.display();coutf3; f3.display();coutf4; f4.display();coutf5; f5.display();if(f1.greaterThan(f2) coutf2endl;if(f2.lessThan(f3) coutf2f3endl;if(f1.equal(f1) coutf1=f1endl;f4=f1.add(f3);coutf4=f1+f3; f4.display();f4=f1.sub(f2);coutf4=f1-f2; f4.display();f4=f1.mul(f3);coutf4=f1*f3; f4.display();f4=f2.div(f3);coutf4=f1/f3; f4.display();f4=f2.reciprocal();coutf4=1/f2; f4.display();f4.input(); coutf4; f4.display();return 0;4.3 构造一个日期时间类（Timedate），数据成员包括年、月、日和时、分、秒，函数成员包括设置日期时间和输出时间，其中年、月请用枚举类型，并完成测试。（包括用成员函数和用普通函数）解：本题要求仅是定义类的练习，并非实用的提供日期时间的程序。实用的日期时间程序见附录二的日期时间函数。#include #include using namespace std;enum YRY2000,Y2001,Y2002,Y2003,Y2004,Y2005;/enum MTJan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov,Dec;class Timedateprivate:YR year;MT month;int date;int hh;int mm;int ss;public:Timedate()year=Y2000;month=Jan;date=1;hh=0;mm=0;ss=0;Timedate(YR a,MT b,int c)year=a;month=b;date=c;hh=12;mm=30;ss=0;void getdate(YR &,MT &,int &);/使用引用一次取得3个数值void gettime(int &,int &,int &);void putdate(YR ,MT ,int );void puttime(int ,int ,int );void list();void Timedate:getdate(YR &y,MT &m,int &d)y=year;m=month;d=date;void Timedate:gettime(int &a,int &b,int &c)a=hh;b=mm;c=ss;void Timedate:putdate(YR a,MT b,int c)year=a;month=b;date=c;void Timedate:puttime(int a,int b,int c)hh=a;mm=b;ss=c;void Timedate:list()/成员函数,直接访问私有的数据成员coutyear/month/date :;switch(year)case Y2000:cout2000;break;case Y2001:cout2001;break;case Y2002:cout2002;break;case Y2003:cout2003;break;case Y2004:cout2004;break;case Y2005:cout2005;break;switch(month)case Jan:cout/Jan;break;case Feb:cout/Feb;break;case Mar:cout/Mar;break;case Apr:cout/Apr;break;case May:cout/May;break;case Jun:cout/Jun;break;case Jul:cout/Jul;break;case Aug:cout/Aug;break;case Sep:cout/Sep;break;case Oct:cout/Oct;break;case Nov:cout/Nov;break;case Dec:cout/Dec;break;cout/dateendl;couthour:minite:second :;couthh:mm:ssendl;int main(int argc, char* argv)Timedate A(Y2004,Mar,3),B;A.list();B.list();B.putdate(Y2005,Oct,18);B.puttime(17,30,00);B.list();return 0;4.4 设计并测试一个矩形类（Rectangle），属性为矩形的左下与右上角的坐标，矩形水平放置。操作为计算矩形周长与面积。测试包括用成员函数和普通函数。解：这里的矩形的4边分别与x轴y轴平行，为最简单的情况。注意参数有缺省值的函数的声明和定义格式。#include #include using namespace std;class Rectangle double left, top ;double right, bottom;public:Rectangle(double l=0, double t=0, double r=0, double b=0); Rectangle(); /析构函数，在此函数体为空void Assign(double l,double t,double r,double b);double getLeft() return left; / 以下四个函数皆为内联成员函数double getRight() return right;double getTop()return top;double getBottom()return bottom;void Show();double Area();double Perimeter();/ 构造函数，带缺省参数，缺省值为全0，在声明中指定Rectangle:Rectangle(double l , double t, double r, double b) left = l; top = t;right = r; bottom = b; void Rectangle:Assign(double l, double t, double r, double b)/赋值left = l; top = t;right = r; bottom = b;void Rectangle:Show()/成员函数直接使用私有的数据成员coutleft-top point is (left,top)n;coutright-bottom point is (right,bottom)n;double Rectangle:Area()return fabs(right-left)*(bottom-top);double Rectangle:Perimeter()return 2*(fabs(right-left)+fabs(bottom-top);int main()Rectangle rect; rect.Show();rect.Assign(100,200,300,400);rect.Show();Rectangle rect1(0,0,200,200);rect1.Show();Rectangle rect2(rect1);rect2.Show();cout面积rect.Area()t周长rect.Perimeter()endl;return 0;4.5 定义一个圆类（Circle），属性为半径（radius）、圆周长和面积，操作为输入半径并计算周长、面积，输出半径、周长和面积。要求定义构造函数（以半径为参数，缺省值为0，周长和面积在构造函数中生成）和拷贝构造函数。解：通常所有数据成员都在构造函数中赋初值。拷贝构造函数以本类的引用为参数。#include#includeusing namespace std;class Circledouble r,Area,Circumference;public:Circle(double a=0);Circle(Circle &);void SetR(double R);double GetR()return r;double GetAreaCircle()return Area;double GetCircumference()return Circumference;Circle:Circle(double a)r=a;Area=r*r*3.14159265;Circumference=2*r*3.14159265;Circle:Circle(Circle & cl)r=cl.r;Area=cl.Area;Circumference=cl.Circumference