Last record of file is repeated twice while using ifstream for opening of file

[nazir hussain]

//The out put of following code gives last record twice. What is wrong. Please help.

#include <iostream>
#include <conio.h>
#include <fstream>
#include <cstdlib>
using namespace std;

struct abc
{
       char code[5],name[15],address[20];
       int pay;
};
main()
{

       abc rec;
       char op;
       int i=0;
       ifstream rrr("employees.dat",ios::in | ios::binary);
       if(!rrr)
       {
                  cerr<<("File opening error")<<endl;
                  getche();
                  exit(1); 
       } 

       while(!rrr.eof()){

                  rrr.read((char*)&rec,sizeof(struct abc));
               
                  cout<<rec.code<<"\t"<<rec.name<<"\t"<<rec.address<<"\t"<<rec.pay<<endl;
                       }
       rrr.close();
       getche();
       return(0);
}

[Oralloy]

A Few Hints

Hello Nazir,

This is pretty obviously a homework, so I'm going to help you find the problem.

Where the problem lies is in your process loop:

       while(!rrr.eof()){

                  rrr.read((char*)&rec,sizeof(struct abc));

                  cout<<rec.code<<"\t"<<rec.name<<"\t"<<rec.address<<"\t"<<rec.pay<<endl;
                       }

First: When is EOF (End Of File) going to be detected?

HINT - your code is reading a fixed number of bytes from a binary file each time through the loop. What are the conditions that cause the EOF?

Second: How will you reconstruct the process loop to handle EOF, when it is detected?

HINT - what is the return value of the read method?

Good Luck!
Oralloy

[nazir hussain]

First of all thank to Mr.Oralloy for help. Actually I am quite new person in learning c++ and have little background of programming. This exercise I copied from a book named "Programmin g with C++ (Aikman series)written by CM Aslam a pakistani author. I am sorry to say that I could not understand your reply. If you are kind enough to help me in detail or give me guidance for a good website from where I can learn c++ to prepare a windows application.
I am again thankfull to you and wish u best wishes.

Regards

Nazir Hussain