程序无法处理多个调用？

Question

我正在为学校创建图书馆系统管理之类的东西

我有这个功能

void Book::AddBook(int index, const string& title, const string& author, const string& publisher, int year)
{
    Book::loadBooks();
    if (index >= 0 && index < maxsize && books[index] == nullptr)
    {
        books[index] = new Book(index, title, author, publisher, year);
        cout << "Book with index " << index << " has been added to the library." << endl;
    }
    else if (index < 0 || index >= maxsize)
    {
        cout << "Error: Book index " << index << " is out of range." << endl;
    }
    else
    {
        cout << "Error: Book with index " << index << " already exists in the library." << endl;
    }
    Book::saveBooks();
}

void Book::saveBooks()
{
    ofstream output("Books.txt");
    if(output.is_open())
    {
        for(int i = 0; i < maxsize; i++)
        {
            if(books[i] != nullptr)
            {
                output << books[i]->getIndex() << ',' << quoted(books[i]->getTitle()) << ',' << quoted(books[i]->getAuthor()) << ',' << quoted(books[i]->getPublisher()) << ',' << books[i]->getYear() << endl;
            }
        }
        output.close();
    }  
}

void Book::loadBooks()
{
    ifstream input("Books.txt");
    if (input.is_open())
    {
        int bookindex, year;
        string title, author, publisher;
        char delimiter;
        while (input >> bookindex >> delimiter >> quoted(title) >> delimiter >> quoted(author) >> delimiter >> quoted(publisher) >> delimiter >> year)
        {
            if (bookindex >= 0 && bookindex < maxsize)
            {
                books[bookindex] = new Book(bookindex, title, author, publisher, year);
            }
        }
        input.close();
    }
}

在我的 main.cpp 中，只有 3 次调用函数，仅此而已。

#include <iostream>
#include "classes.h"
#include "classes.cpp"

int main() {
    Librarian l;
    l.addBook(0, "The Great Gatsby", "F. Scott Fitzgerald", "Charles Scribner's Sons", 1925);
    l.addBook(1, "To Kill a Mockingbird", "Harper Lee", "J. B. Lippincott & Co.", 1960);
    l.addBook(2, "1984", "George Orwell", "Secker & Warburg", 1949);
}

无论何时执行，它只将第一次调用写入文件。如果您对原因有任何想法，请告诉我。

顺便说一句，这是我的析构函数。

Book::~Book()
{
    for (int i = 0; i < maxsize; i++)
    {
        if (books[i] != this && books[i] != nullptr)
        {
            delete books[i];
            books[i] = nullptr;
        }
    }
}

我试过重写加载函数，删除它，整个函数在我脑海里反复了大约 30 分钟，但还是想不出来。