实验、类的重用
【实验目的】
1、理解组合和继承两种类的重用方法的概念和各自适用的情况;
2、掌握C++中以组合方式定义新类及构造对象的方法;
3、掌握C++中以继承方式定义新类及构造对象的方法;
4、掌握多重继承和虚基类。
【实验内容】
设计一个用于人事管理的“People(人员)”基类。考虑到通用性，仅抽象出各类人员都具有的属性 : 编号、姓名、性别、出生日期、身份证号等; 从People(人员)类派生出学生类Student,并添加属性: 班号classNO; 从People类派生出教师)类Teacher, 并添加属性: 职务principalship、部门department;从Student 类中派生出Graduate(研究生)类，添加属性:专业subject、导师adviser (Teacher 类对象); 从Graduate 类和Teacher类派生出助教生类TA。设计时注意虚基类的使用，注意重载相应的成员函数。编写main函数测试这些类。在main 函数中设计测试用例时，注意考虑如何体现成员函数的覆盖。老师将根据设计封装的合理性、测试用例周全性进行评分。
【UML图】
【程序清单】
#include<iostream>
#include<string>
usingnamespace std;
//Date类
classDate
{
public:
Date(int year,int month,int day);
void Show();
private:
intyear,month,day;
};
Date::Date(int year,int month,int day):year(year),month(month),day(day)
{
}
void Date::Show()
{
cout<<year<<"-"<<month<<"-"<<day<<endl;
}
//People类
classPeople
{
public:
People(string id,string name,string gender,Date birthday,string ID_num);
virtualvoid Show();
virtual ~People();
private:
stringid,name,gender,ID_num;
Datebirthday;
};
People::People(string id,string name,string gender,Date birthday,string ID_num):id(id),name(name),gender(gender),ID_num(ID_num),birthday(birthday)
{
}
People::~People()
{
}
void People::Show()
{
cout<<"编号:"<<id<<endl;
cout<<"姓名:"<<name<<endl;
cout<<"性别:"<<gender<<endl;
cout<<"出生日期:";
birthday.Show();
cout<<"身份证号:"<<ID_num<<endl;
}
//Student类
classStudent:virtualpublicPeople
{
public:
Student(People& p,string classNo);
void Show();
private:
stringclassNo;
};
Student::Student(People& p,string classNo):People(p),classNo(classNo)
{
}
void Student::Show()
{
People::Show();
cout<<"班号:"<<classNo<<endl;
}
//Teacher类
classTeacher:virtualpublicPeople
{
public:
Teacher(People& p,string principalship,string department);
string& GetPrincipalship();
string& GetDepartment();
void Show();
private:
stringprincipalship,department;
};
Teacher::Teacher(People& p,string principalship,string department):People(p),principalship(principalship),department(department)
{
}
string& Teacher::GetPrincipalship()
{
returnprincipalship;
}
string& Teacher::GetDepartment()
{
returndepartment;
}
void Teacher::Show()
{
People::Show();
cout<<"职务:"<<principalship<<endl;
cout<<"部门:"<<department<<endl;
}
//Graduate类
classGraduate:publicStudent
{
public:
Graduate(People& p,Student& s,string subject,Teacher& adviser);
void Show();
private:
stringsubject;
Teacheradviser;
};
Graduate::Graduate(People& p,Student& s,string subject,Teacher& adviser):People(p),Student(s),subject(subject),adviser(adviser)
{
}
void Graduate::Show()
{
Student::Show();
cout<<"专业:"<<subject<<endl;
cout<<"导师:"<<endl;
adviser.Show();
}
//TA类
classTA:publicGraduate,publicTeacher
{
public:
TA(People& p,Graduate& g,Teacher& t);
void Show();
};
TA::TA(People& p,Graduate& g,Teacher& t):People(p),Graduate(g),Teacher(t)
{
}
void TA::Show()
{
cout<<"助教信息:"<<endl;
Graduate::Show();
cout<<endl;
cout<<"助教职务:"<<Teacher::GetPrincipalship()<<endl;
cout<<"助教部门:"<<Teacher::GetDepartment()<<endl;;
}
int main()
{
People p1("201308002001","张三","男",Date(1994,1,1),"420001199401012342");
People p2("07005","王五","女",Date(1980,12,12),"126174198012121255");
Student s(p1,"1班");
Teacher t1(p1,"助教","计算机");
Teacher t2(p2,"教授","计算机");
Graduate g(p1,s,"计算机软件与理论",t2);
TA ta(p1,g,t1);
ta.Show();
cout<<"____________________________________________"<<endl<<endl;
Teacher* pt=&ta;//向上转型
pt->Show();//虚函数,函数覆盖,调用ta的Show函数
return 0;
}
【运行结果截图】
【实验小结】
1、充分利用类的重用，用一个类做另一个类的成员；
2、学会类的多重继承；
3、注意充分运用基类的函数，实现代码的重用，而非代码的重复；
4、注意虚基类的运用，特别关注其初始化方式，采用虚基类可以避免二义性的产生；
5、学会使用虚函数，从而实现函数的覆盖，但要注意它的前提是向上转型；
6、注意类封装的完整性；