C++类与对象 怎样把众多函数组合在一起？

定义学生类，并在主函数定义类的对象进行调用测试。
要求： ① 数据成员
② 具有无参和有参的构造函数。
③ 具有深拷贝构造函数。
④ 具有析构函数。
⑤ 具有输出函数、排序函数等。

 #include<iostream>
#include<string>
using namespace std;
class Student{
public:
    int NO=0;
    string name="";
    int score[3] = { 0 };
    double average;
    Student(){}     //无参构造
    Student(int,string,int,int,int );   //构造
    Student(Student &);             //拷贝构造
    void show();
    ~Student() {}                       //析构
};
Student::Student(int id,string name,int score1,int score2,int score3){
    this->NO = id;
    this->name = name;
    this->score[0] = score1;
    this->score[1] = score2;
    this->score[2] = score3;
    this->average = double(score1 + score2 + score3) / 3;
}
Student::Student(Student &other) {
    this->NO = other.NO;
    this->name = other.name;
    for (int i = 0; i < 3; i++)
        this->score[i] = other.score[i];
}
void Student::show() {
    if (NO != 0)
        cout << NO << "\t" << name << "\t" << score[0] << "\t" << score[1] << "\t" << score[2] <<"\t"<<average<< endl;
    else
        cout << "No\tname\tscore1\tscore2\tscore3\taverage" << endl;
}
void sort(Student t[],int len) {
    Student tmp;
    for (int i = 0; i < len - 1; i++) {
        for (int j = i + 1; j < len; j++) {
            if (t[i].average < t[j].average) {
                tmp = t[i];
                t[i] = t[j];
                t[j] = tmp;
            }
        }
    }
}
int main() {
    Student Test[6] = { {},
    {101,"Zhou",93,89,87},
    {102,"Yang",85,80,78},
    {103,"Chen",77,70,83},
    {104,"Qian",70,67,60},
    {105,"Li",72,70,69}};
    for (int i = 0; i < 6; i++)
        Test[i].show();
    sort(Test, 6);
    cout << " 排序后：" << endl;
    for (int i = 0; i < 6; i++)
        Test[i].show();
    return 0;
}