Final working Library system

#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
#include <vector>
#include <sstream>
using namespace std;

void SearchByID(int y);
void DeleteBook(int id);
void SearchByName(char y[]);
void UpdateBook(int id, int ch);


struct Book
{
    char name[50];
    int ID;
    char author[50];
    double price;
    int copies;
};

struct Library
{
    string idd, name, author, price, copies;
    vector<Book> books;
};

string toString(Book & b)
{
    ostringstream OLib;
    OLib << left << setw(4) << b.ID << setw(15) << b.name << setw(15) << b.author << setw(8) << b.price << setw(8) << b.copies << endl;
    return OLib.str();
}

string toString(Library & l)
{
    ostringstream OLib;
    OLib << left << setw(4) << l.idd << setw(15) << l.name << setw(15) << l.author << setw(8) << l.price << setw(8) << l.copies << endl;
    OLib << "=================================================" << endl;
    for (Book & b : l.books) {
        OLib << toString(b);
        OLib << "=================================================" << endl;
    }
    return OLib.str();
}

void WriteFile(Library & library, char x[50])
{
    ofstream OLib(x);
    OLib << left << setw(4) << library.idd << setw(15) << library.name << setw(15) << library.author << setw(8) << library.price << setw(8) << library.copies << endl;
    for (Book &b : library.books)
    {
        OLib << left << setw(4) << b.ID << setw(15) << b.name << setw(15) << b.author << setw(8) << b.price << setw(8) << b.copies << endl;
    }
}

Library ReadFile(char x[50])
{
    ifstream iLib(x, ios::in);
    Library library;
    Book b;
    iLib >> library.idd >> library.name >> library.author >> library.price >> library.copies;
    while (iLib >> b.ID >> b.name >> b.author >> b.price >> b.copies) {
        library.books.push_back(b);
    }
    return library;
}

void BorrowBook(int id)
{
    Library library = ReadFile("library.txt");
    for (Book & b : library.books)
    {
        if (b.ID == id)
            b.copies--;
    }
    WriteFile(library,"library.txt");
}

int main()
{
    ofstream OLib("library.txt", ios::app);
    int choice, id;
    Book book;
    cout << setw(310) << "Library system by MiDo\n" << endl;
    cout << "Choose one of the following:- " << endl;
    cout << "1. Add a new book.\n2. Update a book.\n3. Delete a book.\n4. Show all books.\n5. Search book by ID.\n6. Search book by Name.\n7. Borrow a book.\n8. Exit." << endl;
    cin >> choice;
    while (choice >= 0 && choice < 8) {
        if (choice == 1) {
            cout << "Enter the name of the book you want to add: " << endl;
            getchar();
            cin.get(book.name, 50);
            cout << "Enter the ID of the book you want to add: " << endl;
            cin >> book.ID;
            cout << "Enter the author of the book you want to add: " << endl;
            getchar();
            cin.get(book.author, 50);
            cout << "Enter the price of the book you want to add: " << endl;
            cin >> book.price;
            cout << "Enter the copies of the book you want to add: " << endl;
            cin >> book.copies;
            OLib << left << setw(4) << book.ID << setw(15) << book.name << setw(15) << book.author << setw(8) << book.price << setw(8) << book.copies << endl;
            cout << "Book successfully added!" << endl;
            choice = 0;
        }
        else if (choice == 2) {
            int ch;
            cout << "Enter the ID of the book you want to update." << endl;
            cin >> id;
            cout << "Enter what you want to update :-\n1. Name.\n2. Author.\n3. Price.\n4. No. of copies." << endl;
            cin >> ch;
            UpdateBook(id, ch);
        }
        else if (choice == 3) {
            cout << "Enter the ID of the book you want to delete." << endl;
            cin >> id;
            DeleteBook(id); // Delete a book
            cout << "Book has been deleted! \n" << endl;
        }
        else if (choice == 4) { // show all books
            Library l = ReadFile("library.txt");
            cout << toString(l) << endl;
        }
        else if (choice == 5) {
            int x;
            cout << "Enter the ID you want to search for" << endl;
            cin >> x;
            SearchByID(x);
            choice = 0;
        }
        else if (choice == 6) {
            char x[50];
            cout << "Enter the book name you want to search for" << endl;
            cin >> x;
            SearchByName(x);
            choice = 0;
        }
        else if (choice == 7) {
            int x;
            cout << "Enter the ID of the book you want to borrow" << endl;
            cin >> x;
            BorrowBook(x);
            cout << "Book has been borrowed, Get it back when you finish.\n" << endl;
        }
        else if (choice == 8) {
            return 0;
        }
        cout << "1. Add a new book.\n2. Update a book.\n3. Delete a book.\n4. Show all books.\n5. Search book by ID.\n6. Search book by Name.\n7. Borrow a book.\n8. exit." << endl;
        cin >> choice;
    }
    cout << "Program ended!" << endl;
    system("pause");
    return 0;
}

void SearchByID(int y)
{
    bool found = false;
    Library library = ReadFile("library.txt");
    for (Book &book : library.books) {
        if (book.ID == y) {
            cout << "\nBook is found:\n" << endl;
            cout << left << setw(4) << library.idd << setw(15) << library.name << setw(15) << library.author << setw(8) << library.price << setw(8) << library.copies << endl;
            cout << left << setw(4) << book.ID << setw(15) << book.name << setw(15) << book.author << setw(8) << book.price << setw(8) << book.copies << endl;
            cout << "================================================\n" << endl;
            found = true;
            break;
        }
    }
    if (found == false)
        cout << "Book is not found" << endl;
}

void SearchByName(char y[])
{
    bool found = false;
    Library lib = ReadFile("library.txt");
    for (Book &book : lib.books) {
        if (strcmp(y, book.name) == 0) {
            cout << "\nBook is found:\n" << endl;
            cout << left << setw(4) << lib.idd << setw(15) << lib.name << setw(15) << lib.author << setw(8) << lib.price << setw(8) << lib.copies << endl;
            cout << left << setw(4) << book.ID << setw(15) << book.name << setw(15) << book.author << setw(8) << book.price << setw(8) << book.copies << endl;
            cout << "================================================\n" << endl;
            found = true;
            break;
        }
    }
    if (found == false)
        cout << "Book is not found" << endl;
}

void DeleteBook(int id)
{
    Library library = ReadFile("library.txt");
    for (auto i = library.books.begin(); i != library.books.end(); i++)
    {
        if (i->ID != id)
            continue;
        library.books.erase(i);
        break;
    }
    WriteFile(library, "library.txt");
}

void UpdateBook(int id, int ch)
{
    bool found = false;
    Library library = ReadFile("library.txt");
    ofstream OLib("LibraryTemp.txt");
    char update[50]; int price, copies;
    OLib << left << setw(4) << library.idd << setw(15) << library.name << setw(15) << library.author << setw(8) << library.price << setw(8) << library.copies << endl;
    for (Book &b : library.books)
    {
        if (b.ID == id) {
            found = true;
            if (ch == 1) {
                cout << "Enter the new name you want to update" << endl;
                cin >> update;
                OLib << left << setw(4) << b.ID << setw(15) << update << setw(15) << b.author << setw(8) << b.price << setw(8) << b.copies << endl;
                cout << "Book has been updated! \n" << endl;
            }
            else if (ch == 2) {
                cout << "Enter the new author you want to update" << endl;
                cin >> update;
                OLib << left << setw(4) << b.ID << setw(15) << b.name << setw(15) << update << setw(8) << b.price << setw(8) << b.copies << endl;
                cout << "Book has been updated! \n" << endl;
            }
            else if (ch == 3) {
                cout << "Enter the new price you want to edit" << endl;
                cin >> price;
                OLib << left << setw(4) << b.ID << setw(15) << b.name << setw(15) << b.author << setw(8) << price << setw(8) << b.copies << endl;
                cout << "Book has been updated!\n" << endl;
            }
            else if (ch == 4) {
                cout << "Enter the new copies you want to update" << endl;
                cin >> copies;
                OLib << left << setw(4) << b.ID << setw(15) << b.name << setw(15) << b.author << setw(8) << b.price << setw(8) << copies << endl;
                cout << "Book has been updated! \n" << endl;
            }

        }
        else
            OLib << left << setw(4) << b.ID << setw(15) << b.name << setw(15) << b.author << setw(8) << b.price << setw(8) << b.copies << endl;
    }
    if (found == false)
        cout << "File is not found" << endl;
    library = ReadFile("LibraryTemp.txt");
    WriteFile(library, "library.txt");
}