Сортировка вектора объектов по 3 параметрам

class Book {
private:
    string data; //name of the book
    vector<string> authors;
    int v;
    int d, m, y;
    int pages;
    string plot;
    int id ;
public:
    Book(string data, vector<string> authors, int v, int d, int m, int y, int pages, string plot, int id);
    string GetData();
    string GetAuthor(int i);
    int GetDay();
    int GetMonth();
    int GetYear();
    int GetPages();
    string GetPlot();
    int GetVectorSize();
    /*std::vector<T> GetVectorF() { return v; };*/
    int GetId();
    bool way;
};

bool comparator(Book& book1, Book& book2)
{
    if (book1.GetYear() == book2.GetYear())
    {
        if (book1.GetMonth() == book2.GetMonth())
            return book1.GetDay() < book2.GetDay();
        else
            return book1.GetMonth() < book2.GetMonth();
    }
    else
        return book1.GetYear() < book2.GetYear();
}

std::sort(arr.begin(), arr.end(), comparator);

class Book {
    int d, m, y;
//....остальной код
public:
//....остальной код
    friend bool operator<(Book& book1, Book& book2);
};
 
bool operator<(Book& book1, Book& book2)
{
    if (book1.y == book2.y)
    {
        if (book1.m == book2.m)
            return book1.d < book2.d;
 
        return book1.m < book2.m;
    }
 
    return book1.y < book2.y;
}

std::sort(arr.begin(), arr.end());

bool operator<(Book* book1, Book* book2)
    {
        if (book1->GetYear() == book2->GetYear())
        {
            if (book1->GetMonth() == book2->GetMonth())
                return book1->GetDay() < book2->GetDay();
 
            return book1->GetMonth() < book2->GetMonth();
        }
        return book1->GetYear() < book2->GetYear();
    }
    /*! Add a character.*/
    void AddHero(Node<Book>* r) {
        int a;
        vector<Book*> books;
        vector<string> names;
        int n; string s, data;
        multimap<int, Node<Book>*> role;
        cout << "Enter character name" << endl;
        getline(cin, data);
        cout << "Enter the number of his aliases / names" << endl;
        cin >> n;
        cout << "Fill them in " << endl;
        cin.ignore(1, '\n');
        for (int i = 0; i < n; i++) {
            getline(cin, s);
            names.push_back(s);
        }
        cout << "Enter the number of books in which it appears" << endl;
        cin >> n;
        cout << "Fill the book and its role in it " << endl;
        for (int i = 0; i < n; i++) {
            cout << "Choose book ID" << endl;
            bf.PrintInOrder(r);
            cin >> a;
            Node<Book>* ptr = bf.FindId(a, r);
            cout << "What is his role (1-main, 2-minor, 3-episodic)" << endl;
            cin >> a;
            cin.ignore(1, '\n');
            role.insert(pair<int, Node<Book>*>(a, ptr));
            books.push_back(ptr->data);
        }
        sort(books.begin(), books.end());
        Hero* h = new Hero(data, n, names, role, id, books );
        id++;
        bst.AddLeaf(h, bst.GetRoot());
    }

#include <algorithm>

#include <iostream>
#include <vector>
#include <algorithm>
 
using namespace std;
 
struct str
{
    int x;
    
    str(int a)
    {
        x = a;
    }
};
 
bool comp(str *a, str *b)
{
    if (a->x < b->x)
        return true;
    else
        return false;
}
 
int main()
{
    vector<str *> a;
    a.push_back(new str(2));
    a.push_back(new str(1));
    a.push_back(new str(3));
    sort(a.begin(), a.end(), comp);
 
    for (int i = 0; i < 3; i++)
        cout << a[i]->x << " ";
    
    cout << endl << endl;
        
    str* s[3];
    s[0] = new str(0);
    s[1] = new str(2);
    s[2] = new str(1);
    sort(s, s + 3, comp);
    for (int i = 0; i < 3; i++)
        cout << s[i]->x << " ";
}

   bool comparator( Book* a,  Book* b) {
        if (a->GetYear() < b->GetYear()) return true;
        if (a->GetYear() > b->GetYear()) return false;
        if (a->GetMonth() < b->GetMonth()) return true;
        if (a->GetMonth() > b->GetMonth()) return false;
        return a->GetDay() < b->GetDay();
    }

bool comparator( Book* a,  Book* b)

#include <iostream>
#include <vector>
#include <algorithm>
 
using namespace std;
 
class Book
{
  public:
    string data;
    vector<string> authors;
    int v;
    int d, m, y;
    int pages;
    string plot;
    int id;
public:
    Book(int a, int b, int c) {
        d = a;
        m = b;
        y = c;
    }
};
 
bool comparator(Book *a, Book *b)
{
    if (a->y < b->y) return true;
    if (a->y > b->y) return false;
    if (a->m < b->m) return true;
    if (a->m > b->m) return false;
    return a->d < b->d;
}
 
int main()
{
    vector<Book*> books;
    books.push_back(new Book(1, 2, 3));
    books.push_back(new Book(2, 4, 3));
    books.push_back(new Book(3, 2, 3));
    sort(books.begin(), books.end(), comparator);
    cout << books[2]->d;
}

static bool comparator( Book* a,  Book* b) {
    ...
}

#include <iostream>
#include <vector>
#include <algorithm>
#include <tuple>
 
class Book
{
  public:
    int d{}, m{}, y{};
    int v{};
    int pages{};
    int id{};
    std::string plot;
    std::string data;
    std::vector<std::string> authors;
public:
    Book(int d, int m, int y):d(d),m(m),y(y)
    {
    }
 
    bool operator<(const Book& r)const
    {
        return  std::tie(  y,   m,   d)<
                std::tie(r.y, r.m, r.d);
    }
 
    struct comparator
    {
        bool operator()(const Book& a,const Book& b)const{return a < b;}
        bool operator()(const Book* a,const Book* b)const{return *a < *b;}
    };
};
 
int main()
{
    std::vector<Book*> books
    {
        new Book(1, 2, 3),
        new Book(2, 4, 3),
        new Book(3, 2, 3),
    };
 
    std::sort(books.begin(), books.end(), Book::comparator{});
    
    std::cout << books[2]->d;
    
    for(auto* b:books)delete b;
    books.clear();
}