面向?qū)ο驝習(xí)題參考解答

4-8定義一個(gè)Dog類，包含age,weight等屬性，以及對(duì)這些屬性操作的方法。實(shí)現(xiàn)并測(cè)試這個(gè)類。#include<iostream>usingnamespacestd;classDog{public:voidsetAge(inta){age=a;}intgetAge(){returnage;}voidsetWeight(floatw){weight=w;}floatgetWeight(){returnweight;}private:intage;floatweight;};voidmain(){Dogd;d.setAge(3);d.setWeight(30);cout<<"小狗："<<d.getAge()<<"歲，重"<<d.getWeight()<<"斤。"<<endl;}4-9設(shè)計(jì)并測(cè)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<iostream>#include<math.h>usingnamespacestd;classRectangle{public:Rectangle(intxx1,intyy1,intxx2,intyy2){x1=xx1;y1=yy1;x2=xx2;y2=yy2;}floatgetArea(){returnfabs(x2-x1)*fabs(y2-y1);}private:intx1,y1;intx2,y2;};voidmain(){Rectanglerec(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<iostream>usingnamespacestd;classRectangle{public:Rectangle(intl,intw){length=l;width=w;}floatgetArea(){returnlength*width;}private:intlength;intwidth;};voidmain(){Rectanglerec(10,20);cout<<"矩形面積："<<rec.getArea()<<endl;}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(duì)象進(jìn)行測(cè)試。#include<iostream>usingnamespacestd;constfloatPI=3.1415;classCircle{public:Circle(floatr){radius=r;}floatgetArea(){returnradius*PI*PI;}private:floatradius;};voidmain(){Circlec(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工作。Complexc1(3,5);Complexc2=4.5;c1.add(c2);c1.show();//源程序如下：#include<iostream>usingnamespacestd;classComplex{public:Complex(floatr=0.0,floati=0.0){real=r;image=i;}voidadd(Complexb){real=real+b.real;image=image+b.image;}voidshow(){cout<<real<<"+"<<image<<"i"<<endl;}private:floatreal;//實(shí)部floatimage;//虛部};voidmain(){Complexc1(3,5);Complexc2=4.5;//相當(dāng)于Complexc2(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(cè)試這個(gè)類，體會(huì)靜態(tài)數(shù)據(jù)成員和靜態(tài)成員函數(shù)的用法。#include<iostream>usingnamespacestd;classCat{public:Cat(){numOfCats++;}~Cat(){numOfCats--;}staticintgetNumOfCats(){returnnumOfCats;}private:staticintnumOfCats;};intCat::numOfCats=0;voidmain(){cout<<"現(xiàn)在的Cat數(shù)量："<<Cat::getNumOfCats()<<endl;Cata;cout<<"現(xiàn)在的Cat數(shù)量："<<a.getNumOfCats()<<endl;Catb;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<iostream>usingnamespace