学生类的创建与完善，如何解决

Question

//1.定义一个学生类，包含姓名、年龄、绩点，要求能够初始化学生信息（定义常规构造函数和拷贝构造函数）、显示学生信息、设置学生信息；
//
//2.在主函数中定义一个学生数组（普通数组或者动态数组都可以），大小为5，然后利用设置学生信息的成员函数输入每个学生信息；
//
//3.定义student类的友元函数Sort实现按绩点排序，以对象指针（或对象数组）和数组大小为参数，对学生按绩点由高到低排序。
// 在主函数中调用函数sort，输出排序后的学生信息。
//
//在此基础上，为student类增加：
//
//（1）静态数据成员 count, 负责统计学生总数，并实现其值的更新；
//
//（2）Date 类的成员对象 birthday, 并为student类定义相应的构造函数；
#include<iostream>
#include<string>
using  namespace  std;
class  Date
{
    int  year;
    int  month;
    int  day;
public:
    Date(int  year = 0, int  month = 0, int  day = 0);
    int  Getyear() { return  year; }
    int  Getmonth() { return  month; }
    int  Getday() { return  day; }
};
//************************
Date::Date(int  year, int  month, int  day)
{
    this->year = year;
    this->month = month;
    this->day = day;
}
//*************************

class  Student
{
    static  int  Count;
    string  Name;
    int  Age;
    double  Point;
    Date  Birthday;
public:
    Student();
    Student(string  name, int  age, double  point, Date  birthday);
    Student(const  Student& a);
    ~Student();
    int  Getcount();
    void  Show();
    void  Set(string  name, int  age, double  point, Date  birthday);
    friend  void  Sort(Student  a[], int  b);
};
//****************************

int Student::Count = 0;
Student::Student()
{
    this->Name = "0";
    this->Age = 0;
    this->Point = 0;
    this->Birthday = 0;
}
Student::Student(string  name, int  age, double  point, Date  birthday)
{
    this->Name = name;
    this->Age = age;
    this->Point = point;
    this->Birthday = birthday;
}
Student::Student(const  Student& a)
{
    this->Name = a.Name;
    this->Age = a.Age;
    this->Point = a.Point;
    this->Birthday = a.Birthday;
}
Student::~Student()
{

}
int Student::Getcount()
{
    Count = 5;
    return Count;
}
void Student::Show()
{
    cout << this->Name << "    " << this->Age << "    "
        << "    " << this->Point << endl;
}
void  Student::Set(string  name, int  age, double  point, Date  birthday)
{
    this->Name = name;
    this->Age = age;
    this->Point = point;
    this->Birthday = birthday;
}
void Sort(Student  a[], int  b)
{
    for (int i = 0; i < b; i++)
    {
        for (int j = i + i; j < b; j++)
        {
            if (a[i].Point < a[j].Point)
            {
                Student temp = a[i];

                a[i] = a[j];
                a[j] = temp;
            }
        }
    }
}


//**********************
int  main()
{
    cout << "请输入学生信息：" << endl;
    string  name; int  age; double  point;
    int  year, month, day;
    Student  a[5];
    for (int i = 0; i < 5; i++)
    {
        cin >> name >> age >> point >> year >> month >> day;
        Date  birthday(year, month, day);
        a[i].Set(name, age, point, birthday);
    }
    Sort(a, 5);
    cout << "共有学生" << a[0].Getcount() << "名。" << endl;
    cout << "分别为：" << endl;
    for (int i = 0; i < 5; i++)
    {
        a[i].Show();
    }
    return  0;
}

Answer 1

以下是实现该功能的代码示例（包含对Date类的定义）：

#include <iostream>
#include <string>
#include <algorithm>
using namespace std;

// Date 类定义，用于保存学生的出生日期
class Date {
public:
    Date(int y, int m, int d) : year(y), month(m), day(d) {}
    friend bool operator< (const Date& lhs, const Date& rhs);
    friend bool operator== (const Date& lhs, const Date& rhs);
    friend ostream& operator<< (ostream& os, const Date& date);
private:
    int year;
    int month;
    int day;
};

bool operator< (const Date& lhs, const Date& rhs) {
    if (lhs.year != rhs.year) {
        return lhs.year < rhs.year;
    }
    else if (lhs.month != rhs.month) {
        return lhs.month < rhs.month;
    }
    else {
        return lhs.day < rhs.day;
    }
}

bool operator== (const Date& lhs, const Date& rhs) {
    return lhs.year == rhs.year && lhs.month == rhs.month && lhs.day == rhs.day;
}

ostream& operator<< (ostream& os, const Date& date) {
    os << date.year << "/" << date.month << "/" << date.day;
    return os;
}

// Student 类定义，用于保存学生的信息
class Student {
public:
    Student() : name(""), age(0), score(0.0), birthday(2000, 1, 1) {
        ++count;
    }
    Student(const string& name_, int age_, double score_, const Date& birthday_)
        : name(name_), age(age_), score(score_), birthday(birthday_) {
        ++count;
    }
    Student(const Student& other) {
        name = other.name;
        age = other.age;
        score = other.score;
        birthday = other.birthday;
        ++count;
    }
    ~Student() {
        --count;
    }
    // 访问器和修改器
    string getName() const { return name; }
    void setName(const string& name_) { name = name_; }
    int getAge() const { return age; }
    void setAge(int age_) { age = age_; }
    double getScore() const { return score; }
    void setScore(double score_) { score = score_; }
    // 友元函数
    friend void Sort(Student* arr, int size);
    friend ostream& operator<< (ostream& os, const Student& student);
private:
    string name;
    int age;
    double score;
    Date birthday;
    static int count;
};

int Student::count = 0;

// 比较函数，用于排序
bool cmp(const Student& lhs, const Student& rhs) {
    return lhs.score > rhs.score;
}

// Sort 函数，用于按照绩点排序
void Sort(Student* arr, int size) {
    sort(arr, arr + size, cmp);
}

ostream& operator<< (ostream& os, const Student& student) {
    os << "姓名：" << student.name << "，年龄：" << student.age 
        << "，绩点：" << student.score << "，出生日期：" << student.birthday;
    return os;
}

int main() {
    // 定义学生数组
    Student students[5];

    // 输入学生信息
    for (int i = 0; i < 5; ++i) {
        string name;
        int age;
        double score;
        int year, month, day;
        cout << "请输入第" << i + 1 << "个学生的信息：" << endl;
        cout << "姓名：";
        cin >> name;
        cout << "年龄：";
        cin >> age;
        cout << "绩点：";
        cin >> score;
        cout << "出生年份：";
        cin >> year;
        cout << "出生月份：";
        cin >> month;
        cout << "出生日期：";
        cin >> day;
        students[i] = Student(name, age, score, Date(year, month, day));
    }

    // 按照绩点排序
    Sort(students, 5);

    // 输出学生信息
    cout << endl;
    for (int i = 0; i < 5; ++i) {
        cout << students[i] << endl;
    }

    // 输出学生总数
    cout << endl << "学生总数为：" << Student::count << endl;

    return 0;
}