C++ file read error in Debug mode in Visual C++

Question

I am trying to create a simple program to read and write Book(title,author,id,price,edition) object into a file. The code is able to successfully write the Book objects to file and the read operation is also successful but while exiting that init method "Memory Read Access Violation is encountered". Also I am getting this error in Debug mode , while in Release mode the code works fine.

File format: I firstly save the number of records(int) and then write each object(Book) one by one.

While exiting from init() , the error is occurring.

Why this error is occurring ? and please don't tell to use other libraries like Boost , I am trying to do in without any library.

Also I haven't implemented other interface methods.

    //Book.h
    #pragma once
    #include<iostream>
    #include<string>
    using namespace std;
    class Book
    {
    public:
        Book();
        Book(string title, string author, string id, float price, int edition);
        void show() const;

        string title, author, id;
        float price;
        int edition;
    };

//Book.cpp
#include "Book.h"

Book::Book() :Book("UNDEFINED", "UNDEFINED", "UNDEFINED", 0, 0){}

Book::Book(string title, string author, string id, float price, int edition) :title(title), author(author), id(id), price(price), edition(edition)
{
}
void Book::show() const{
    cout << title << " by : " << author << endl;
    cout << "ID : " << id << " ,  PRICE : " << price << " ,  EDITION : " << edition << endl;
}








 //BookManager.h
#pragma once
#include"Book.h"
#include<vector>
#include<fstream>

class BookManager
{
public:
    BookManager();
    ~BookManager();

    void add(const Book b);
    void list() const;
    void update(string id, const Book b);
    void remove(string id);

private:

    vector<Book> db;
    ofstream out;
    ifstream in;

    void init();
    void save();
};



 //BookManager.cpp
#include "BookManager.h"

BookManager::BookManager(){
    init();
}

BookManager::~BookManager()
{
    save();
}

void BookManager::add(const Book b){
    db.push_back(b);
}
void BookManager::list()const {
    for (const Book &b : db){
        cout << "\n-----------------------------------\n";
        b.show();
    }
    cout << "-----------------------------------\n";
}
void BookManager::update(string id, const Book b){
}
void BookManager::remove(string id){
}
void BookManager::init(){
    in.open("data.txt", ios::in, ios::binary);
    if (!in.is_open())
    {
        throw " >> Unable to init app";
    }

    int size;
    in >> size;

    Book book;

    for (int i = 0; i < size; i++)
    {
        in.read((char*)&book, sizeof(Book));
        db.emplace_back(book.title, book.author, book.id, book.price, book.edition);
    }

    in.close();// error is occuring here according to debugger
}
void BookManager::save(){
    out.open("data.txt", ios::out, ios::binary);
    if (!out.is_open())
    {
        throw " >> Unable to save";
    }
    int size = db.size(); 

    out << size;

    for (const Book c : db)
    {
        out.write((char*)&c, sizeof(Book));
    }

    out.close();
}









 //Test.cpp
#include<iostream>
#include<conio.h>
#include"BookManager.h"
using namespace std;

void showMenu();

void main(){
    try{


        Book book;
        string key;
        bool continueApp = true;
        BookManager mgr;


        while (continueApp)
        {
            showMenu();
            int choice = _getch() - '0';

            switch (choice)
            {
            case 1:
                cout << " Title : ";
                cin >> book.title;
                cout << " Author : ";
                cin >> book.author;
                cout << " ID : ";
                cin >> book.id;
                cout << " Price : ";
                cin >> book.price;
                cout << " Edition : ";
                cin >> book.edition;
                mgr.add(book);
                break;
            case 2:
                mgr.list();
                break;
            case 3:
                break;
            case 4:
                break;
            case 5:
                continueApp = false;
                break;
            default:
                cerr << " >> Invalid Choice ! \n";
                break;
            }
        }
    }
    catch (char *ex){
        cerr << ex << endl;
    }
}

void showMenu(){
    cout << "\n ___________________________ \n";
    cout << " 1) Add contact" << endl;
    cout << " 2) List contacts" << endl;
    cout << " 3) Remove contact" << endl;
    cout << " 4) Update contact" << endl;
    cout << " 5) Exit app" << endl;
    cout << "___________________________ \n";
}