/*
   lab10b.cpp
   7/4/2005
   CIS 150
   David G. Klick
   
   Demonstrates reading structures from a binary file.
*/

#include <iostream>
#include <iomanip>
#include <fstream>
#include <cstring>
using std::cout;
using std::ifstream;
using std::ofstream;
using std::ios;
using std::setw;
using std::setprecision;
using std::showpoint;
using std::fixed;

struct Book {
   char title[40];
   char author[35];
   double price;
   int quantity;
};

void display(Book b);

int main(void) {
   ifstream ifile;  // used to handle input file
   long numrecs;
   
   // create three book objects
   Book book1, book2, book3;
   
   // open random access file to read in books
   ifile.open("books.dat", ios::in | ios::binary);
   
   // display error if could not open file
   if (!ifile) {
      cout << "Error: Could not open input file!\n";
      return 1;
   }

   // find out how many records are in file
   ifile.seekg(0L, ios::end);  // go to end of file
   numrecs = ifile.tellg() / sizeof(Book);
   ifile.seekg(0L, ios::beg);  // go to start of file
   
   // display error if not three books in file
   if (numrecs != 3) {
      cout << "Error: " << numrecs << " books in file.\n";
      return 2;
   }
   
   // read book objects from file
   ifile.read((char*)&book1, sizeof(Book));
   ifile.read((char*)&book2, sizeof(Book));
   ifile.read((char*)&book3, sizeof(Book));

   // close file
   ifile.close();
   
   // display book info read from file
   cout << "Book information read from file:\n   ";
   display(book1);
   cout << "\n   ";
   display(book2);
   cout << "\n   ";
   display(book3);
   cout << '\n';
   
   return 0;
}

void display(Book b) {
   cout << b.title << ", by " << b.author
        << " (" << b.quantity << " @ $"
        << fixed << showpoint << setprecision(2)
        << b.price << ')';
}