C++继承和派生练习(一)--关于从people(人员)类派生出student(学生)类等

 . 从people(人员)类派生出student(学生)类
添加属性：班号char classNO[]；从people类派生出teacher(教师)类，
添加属性：职务char  principalship[]、部门char department[]。
从student类中派生graduate(研究生)类，添加属性：专业char subject[]、
导师char teacher_adviser[]；从graduate类和teacher类派生出TA(助教生)类，
注意虚基类的使用。重载相应的成员函数，测试这些类。
 . 代码如下：
```
#include<iostream>
#include<string>
#include<cstring>
#include<cstdio>
#include<cstdlib>
using namespace std;
class Data {
public:
    Data() {}
    Data(int yy, int mm, int dd);
    Data(Data &ap);
    ~Data();
    int get_year();
    int get_month();
    int get_day();
    void set_year(int y);
    void set_month(int m);
    void set_day(int d);
private:
    int year;
    int month;
    int day;
};
Data::Data(int yy, int mm, int dd) {
    year = yy;
    month = mm;
    day = dd;
}
Data::Data(Data &ap) {
    year = ap.year;
    month = ap.month;
    day = ap.day;
}
Data::~Data() {

}
int Data::get_day() {
    return day;
}
int Data::get_month() {
    return month;
}
int Data::get_year() {
    return year;
}
void Data::set_day(int d) {
    day = d;
}
void Data::set_month(int m) {
    month = m;
}
void Data::set_year(int y) {
    year = y;
}
class People {
public:
    People(int num, string se, Data birthd, string iid);
    People(People &tp);
    People() {}
    People get_People();
    ~People() {

    }
    void set_number(int num) {
        number = num;
    }
    void set_sex(string se) {
        sex = se;
    }
    void set_birthday(Data birth) {
        birthday = birth;
    }
    void set_id(string iidd) {
        id = iidd;
    }
    int get_number();
    string get_sex();
    Data get_birthday();
    string get_id();
    void details();
private:
    int number;
    string sex;
    Data birthday;
    string id;
};
inline int People::get_number() {
    return number;
}
inline string People::get_sex() {
    return sex;
}
inline string People::get_id() {
    return id;
}
Data People::get_birthday() {
    return birthday;
}
void People::details() {
    cout << "Number:" << number << endl;
    cout << "Sex:" << sex << endl;
    cout << "Birhtday:" << birthday.get_year() << "/" << birthday.get_month() << "/" << birthday.get_day() << endl;
    cout << "ID:" << id << endl;
}
People::People(int num, string se, Data birth, string iid) :birthday(birth) {
    number = num;
    sex = se;
    id = iid;
}
People People::get_People() {
    int num, yy, mm, dd;
    string ID, se;
    cout << "Please enter the number of the people:";
    cin >> num;
    cout << "Please enter the sex of the people:(male or female)";
    cin >> se;
    cout << "Please enter the birthday of the people:" << endl
        << "(Warnning:The format is similar to 1998 8 3)" << endl;
    cin >> yy >> mm >> dd;
    cout << "Please enter the id of the people:";
    cin >> ID;
    Data birth(yy, mm, dd);
    id = ID;
    number = num;
    sex = se;
    birthday = birth;
    return *this;
}
People::People(People &tp) {
    number = tp.get_number();
    sex = tp.get_sex();
    id = tp.get_id();
    birthday = tp.get_birthday();
}
class Student :virtual public People {
public:
    char classNo[];
    Student(int num, string se, Data birthd, string iid, char a[]) :People(num, se, birthd, iid) {
        strcpy(classNo, a);
    }
    ~Student() {

    };
    void Show_Student() {
        cout << "This is student:" << endl;
        cout << "ClassNo :" << classNo << endl;
    }
};
class Teacher :virtual public People {
public:
    char principalship[];
    char department[];
    Teacher(int num, string se, Data birthd, string iid, char a[],char b[]) :People(num, se, birthd, iid) {
        strcpy(principalship, a);
        strcpy(department, b);
    }
    Teacher() {

    }
    void Show_Teacher() {
        cout << "This is teacher:" << endl;
        cout << "Principalship :" << principalship << endl;
        cout << "Department :" << department << endl;
    }
};
class Graduate :virtual public Student {
public:
    char subject[];
    Teacher adviser;
    Graduate(int num, string se, Data birthd, string iid, char a[], char c[],Teacher vt) :People(num, se, birthd, iid), Student(num, se, birthd, iid, a) {
        strcpy(subject, c);
        adviser = vt;
    }
    ~Graduate() {

    }
    void Show_Graduate() {
        cout << "This is Graduate:" << endl;
        cout << "The subject:" << subject << endl;
        cout << "The adviser teacher:" << endl;
        cout << "Principalship:" << adviser.principalship<< endl;
        cout << "Department:" << adviser.department << endl;
        cout << endl;
    }
};
class TA :public Graduate, public Teacher {
    TA(int num, string se, Data birthd, string iid, char a[], char c[], Teacher vt) :People(num, se, birthd, iid), Student(num, se, birthd, iid, a), Graduate(num, se, birthd, iid, a, c, vt) {

    }
    ~TA() {

    }
    void Show_TA() {
        cout << "This is TA:" << endl;
        cout << "The classNo:" << classNo << endl;
    }
};
int main()
{
    People asp;
    asp.get_People();
    asp.details();
    Data a(, , );
    Student b(,"male",a,"","");
    b.Show_Student();
    Data a1(, , );
    Teacher c(, "female", a1,"","Advanced", "Promotion");
    c.Show_Teacher();
    Data a2(, , );
    Graduate d(, "female", a2, "", "", "CS", c);
    d.Show_Graduate();
    return ;
}
```