C++上机实验报告实验六

1、实验六 多态性1. 实验目的1.掌握运算符重载的方法2.学习使用虚函数实现动态多态性2. 实验要求1.定义Point类，有坐标_x，_y两个成员变量；对Point类重载“”(自增)、“”(自减)运算符，实现对坐标值的改变。2.定义一个车(vehiele)基类，有Run、Stop等成员函数，由此派生出自行车(bicycle)类、汽车(motorcar)类，从bicycle和motorcar派生出摩托车(motorcycle)类，它们都有Run、Stop等成员函数。观察虚函数的作用。3. (选做)对实验4中的People类重载“”运算符和“=”运算符，“”运算符判断两个people类对象的id属性

2、是否相等；“=”运算符实现People类对象的赋值操作。3. 实验内容及实验步骤1.编写程序定义Point类，在类中定义整型的私有成员变量_x_y，定义成员函数Point& operator+()；Point operator+(int)；以实现对Point类重载“+”(自增)运算符，定义成员函数Point operator()；Point operator(int)；以实现对Point类重载“”(自减)运算符，实现对坐标值的改变。程序名：1ab8_1cpp。2.编写程序定义一个车(vehicle)基类，有Run、Stop等成员函数，由此派生出自行车(bicycle)类、汽车(motorcar

3、)类，从bicycle和motorcar派生出摩托车(motorcycle)类，它们都有Run、Stop等成员函数。在main()函数中定义vehicle、bicycle、motorcar、motorcycle的对象，调用其Run()、Stop()函数，观察其执行情况。再分别用vehicle类型的指针来调用这几个对象的成员函数，看看能否成功；把Run、Stop定义为虚函数，再试试看。程序名：lab8_2cpp。4. 思考题1. 如何将一个运算符重载为类的成员函数？函数类型 operator 运算符（形参表） 函数体；2. 如何将一个运算符重载为类的友元函数？friend 函数类型 operat

4、or 运算符（形参表） 函数体；3.如何实现运行时刻的多态？在基类的成员函数前加上virtual，就可以在它的派生类中声明相同名字和类型的成员函数，在运行过程中，系统会自动判断并调用相应类中的成员函数，从而在调用过程中实现多态。5. 源程序1. lab8_1.cpp#includeusing namespace std;class Pointprivate: int _x; int _y;public: /构造.析构函数 Point() Point(int,int); Point() /+.-重载 Point& operator +(); Point operator +(int); Poin

5、t& operator -(); Point operator -(int); /输出点坐标 void showPoint();Point:Point(int x,int y) _x=x; _y=y;Point& Point:operator +() _x+; _y+; return *this;Point Point:operator +(int) Point p=*this; +(*this); return p;Point& Point:operator -() _x-; _y-; return *this;Point Point:operator -(int) Point p=*thi

6、s; -(*this); return p;void Point:showPoint() coutThe point is (_x,_y)endl;int main() Point apoint(3,5); apoint.showPoint(); (apoint+).showPoint();/测试后置+ apoint.showPoint(); (+apoint).showPoint();/测试前置+ apoint.showPoint(); (apoint-).showPoint();/测试后置- apoint.showPoint(); (-apoint).showPoint();/测试前置-

7、apoint.showPoint(); return 0;2. lab8_2.cpp#includeusing namespace std; class Vehiclepublic: /基类的成员函数为虚函数 virtual void run()coutVehicle is running!endl; virtual void stop()coutVehicle is stopping!endl;class Bicycle: virtual public Vehicle/按虚基类继承public: void run()coutBicycle is running!endl; void stop

8、()coutBicycle is stopping!endl;class Motorcar:virtual public Vehicle/按虚基类继承public: void run()coutMotorcar is running!endl; void stop()coutMotorcar is stopping!endl;class Motorcycle:public Bicycle,public Motorcarpublic: void run()coutMotorcycle is running!endl; void stop()coutMotorcycle is stopping!r

9、un(); p-stop(); p=&bic; p-run(); p-stop(); p=&mot; p-run(); p-stop(); p=&m; p-run(); p-stop(); return 0;3. lab8_3#include#includeusing namespace std;/Date类class Dateprivate:int year;int month;int day;public:Date();Date(int y,int m,int d);Date(Date &p);Date();void setDate();void showDate();/People类，其

10、中含Date类型的数据class Peopleprivate:char name11;char number7;char sex3;Date birthday;public:char id16;People();People(char* n,char* nu,char* s,Date b,char* i);People(People &p);People();bool operator =(People&);People& operator =(People&);void setName();void setNumber();void setSex();void setId();void sh

11、owPeople();/Date构造函数Date:Date()Date:Date(int y,int m,int d)year=y;month=m;day=d;Date:Date(Date &p)year=p.year;month=p.month;day=p.day;/析构inline Date:Date()/Date成员函数，设置出生年月日void Date:setDate()int y,m,d;couty;coutm;coutd;year=y;month=m;day=d;/Date内联成员函数，输出年月日inline void Date:showDate()coutBirthday is

12、year年month月day日endl;/People构造函数People:People();People:People(char* n,char* nu,char* s,Date b,char* i)strcpy(name,n);strcpy(number,nu);strcpy(sex,s);birthday=b;strcpy(id,i);People:People(People &p)strcpy(name,);strcpy(number,p.number);birthday=p.birthday;strcpy(id,p.id);/People析构inline People:P

13、eople()/People成员函数，设置各类数据void People:setName()coutPlease input the persons name:;cin.getline(name,11,n);void People:setNumber()coutInput number:;cin.getline(number,7,n);void People:setSex()coutInput sex:;cin.getline(sex,3,n);void People:setId()coutInput id:;cin.getline(id,16,n);/People内联成员函数，输出人员信息i

14、nline void People:showPeople()coutName:nameendl;coutNumber:numberendl;coutSex:sexendl;coutID:idendl;bool People:operator =(People& p)return id=p.id;People& People:operator =(People& p)strcpy(name,);strcpy(number,p.number);birthday=p.birthday;strcpy(id,p.id);return *this;/检测=重载的普通函数void test(Pe

15、ople& x,People& y)if(strcmp(x.id,y.id)=0)coutTheirs IDs are sameendl;elsecoutTheirs IDs are differentendl;int main()/*int i;char spaceA;/生成3个Date类型的对象Date date3=Date(0,0,0),Date(0,0,0),Date(0,0,0);/生成3个People类型的对象People person3=People(0,0,0,date0,0),People(0,0,0,date1,0),People(0,0,0,date2,0);/设置这3个

16、对象的各类信息for(i=0;i3;i+)personi.setName();personi.setNumber();personi.setSex();personi.setId();datei.setDate();spaceA=getchar();/输出这3个对象的各类信息for(i=0;i3;i+)personi.showPeople();datei.showDate();*/测试=重载Date d1(0,0,0);People p1(lizhibo,01,male,d1,);People p2(wangyusen,02,male,d1,123); People p3(zhouhao,03,male,d1,);test(p1,p2);test(p1,p3);/测试=重载coutBefore =endl;p1.showPeople();p1=p3;coutAfter =endl;p1.showPeople();return 0;6. 运行结果1. 2.直接使用对象.函数的形式可以成功调用函数