Question

Write a menu driven program in C++ to perform the following functions on a binary file “BOOK.DAT” containing objects of the following class:
class Book
{ int BookNo;
char Book_name[20];
public:
// function to enter book details
void enterdetails();
//function to display Book details
void showdetails();
//function to return Book_no
int Rbook_no() {return Book_no;}
//function to return Book_name
int Rbook_name() {return Book_name;}

};
1. Append Records
2. Modify a record for a given book no.
3. Delete a record with a given book no.
4. Search for a record with a given Book name

Answer 1

Book.h

#include <iostream>
#include <stdio.h>
using namespace std;
class Book {
public:
    int Book_no;
    char Book_name[20];
    Book() {
    }
    void enterdetails() {
        cout << "Enter No ";
        cin >> Book_no;
        cout << "Enter name ";
        cin >> Book_name;
        if (Book_no < 0) {
            throw exception();
        }
    }
    void showdetails() {
        cout << Book_no << " - " << Book_name << endl;
    }
    // function to return Book_no
    int Rbook_no() {
        return Book_no;
    }
};
//function to return Book_name
char* Rbook_name() {
    return Book_name;
}

Main.cpp

//==============================================================

// Name : Question47279.cpp

// Author :

// Version :

// Copyright : Your copyright notice

// Description : Hello World in C++, Ansi-style

//==============================================================

#include <iostream>
#include <cstdlib>
#include <stdio.h>
#include <string>
#include <fstream>
#include <vector>
#include "Book.h"
using namespace std;
const int DELETED = -1;
vector<Book> books;
void read() {
    ifstream in("test.dat");
    if (!in.good()) {
        return;
    }
    while (!in.eof())
    {
        Book curBook = Book();
        in >> curBook.Book_no;
        in >> curBook.Book_name;
        books.push_back(curBook);
    }
    in.close();
    size_t booksAmount = books.size();
    for (size_t i = 0; i < booksAmount; ++i) {
        books[i].showdetails();
    }
}
void rewriteFile() {
    ofstream outfile;
    outfile.open("test.dat");
    size_t nBooks = books.size();
    for (size_t i = 0; i < nBooks; ++i) {
        if (books[i].Book_no != DELETED) {
            outfile << books[i].Book_no << books[i].Book_name;
        }
    }
}
void appendBook() {
    Book newBook = Book();
    newBook.enterdetails();
    books.push_back(newBook);
    rewriteFile();
}
void modifyBook() {
    cout << "Enter book No ";
    int n;
    cin >> n;
    if (n > 0) {
        int found = DELETED;
        size_t nBooks = books.size();
        for (size_t i = 0; i < nBooks; ++i) {
            if (books[i].Book_no == n) {
                found = i;
            }
        }
        if (found != DELETED) {
            cout << "Enter new name ";
            cin >> books[found].Book_name;
        }
    }
    rewriteFile();
}
void searchBook() {
    cout << "Enter book name ";
    char val[20];
    cin >> val;
    bool found = false;
    size_t nBooks = books.size();
    for (size_t i = 0; i < nBooks; ++i) {
        if (strcmp(books[i].Book_name, val) == 0) {
            books[i].showdetails();
            found = true;
        }
    }
    if (!found) {
        cout<<"No results found"<<endl;
    }
    rewriteFile();
}
void deleteBook() {
    cout<<"Enter book No ";
    int n;
    cin>>n;
    if (n > 0) {
        size_t nBooks = books.size();
        for (size_t i = 0; i < nBooks; ++i) {
            if (books[i].Book_no == n) {
                books[i].Book_no = DELETED;
            }
        }
    }
    rewriteFile();
}
int main() {
    char res = ' ';
    bool quit = false;
    while (!quit) {
        cout<<"---Content of dat file---"<<endl<<endl;
        read();
        cout<<endl<<"---"<<endl;
        cout<<"What do you want to do?"<<endl;
        cout<<"1 - Add new book"<<endl;
        cout<<"2 - Modify book"<<endl;
        cout<<"3 - Delete book"<<endl;
        cout<<"4 - Search book"<<endl;
        cout<<"q - Quit"<<endl;
        cin>>res;
        switch (res) {
            case '1':
                appendBook();
                break;
            case '2':
                modifyBook();
                break;
            case '3':
                deleteBook();
                break;
            case '4':
                searchBook();
                break;
            case 'q':
                quit = true;
                break;
        }
    }
    return 0;
}