dev-cpp-users

[Dev-C++] feof question

[Sam <sch...@ho...>]

I'm trying to read through a file using the following statement:

while(!feof(filePtr)
{
   fread(&phone, sizeof(struct record), 1, filePtr);
   printf("%d%s", int, name);
   count++;
}

The problem is that it reads the last record twice and increments the =
count one more time than needed.  Could someone explain why this happens =
and how to avoid it using the feof function?  Thanks.

Sam

Re: [Dev-C++] feof question

[Vassili <v.v...@bt...>]

you can use the fread in the while, when the eof is read it exits the =
loop

while(fread(&phone, sizeof(struct record), 1, filePtr))
{  =20
   printf("%d%s", int, name);
   count++;
}
  ----- Original Message -----=20
  From: Sam=20
  To: dev...@li...=20
  Sent: Saturday, March 17, 2001 6:00 PM
  Subject: [Dev-C++] feof question


  I'm trying to read through a file using the following statement:

  while(!feof(filePtr)
  {
     fread(&phone, sizeof(struct record), 1, filePtr);
     printf("%d%s", int, name);
     count++;
  }

  The problem is that it reads the last record twice and increments the =
count one more time than needed.  Could someone explain why this happens =
and how to avoid it using the feof function?  Thanks.

  Sam

RE: [Dev-C++] feof question

[Ioannis V. <no...@ya...>]

You can also use :

do
{
/* ... */
}while(!feof(filePtr));

In this way you gain one less check for end of file (where performance is
important).


About the second read of the "same data" at the end:

This happens because the end of file is true only after a failed attempt
(because the end of file has been already reached and it has no more to
read). That means it doesn't read the data for the second time, but you have
a failed attempt to read more data.
  As for the counter you can either decrease it by one after the loop or
initialize it with -1.


Ioannis

* Ioannis Vranos
* Programming pages: http://members.nbci.com/noicys
* Alternative URL: http://run.to/noicys
  -----Original Message-----
  From: dev...@li...
[mailto:dev...@li...]On Behalf Of Sam
  Sent: Saturday, March 17, 2001 8:01 PM
  To: dev...@li...
  Subject: [Dev-C++] feof question


  I'm trying to read through a file using the following statement:

  while(!feof(filePtr)
  {
     fread(&phone, sizeof(struct record), 1, filePtr);
     printf("%d%s", int, name);
     count++;
  }

  The problem is that it reads the last record twice and increments the
count one more time than needed.  Could someone explain why this happens and
how to avoid it using the feof function?  Thanks.

  Sam

Re: [Dev-C++] feof question

[Sam <sch...@ho...>]

Thanks for all the suggestions.  I'll try them out...

Sam
  ----- Original Message -----=20
  From: Ioannis Vranos=20
  To: dev...@li...=20
  Sent: Saturday, March 17, 2001 3:25 PM
  Subject: RE: [Dev-C++] feof question


  You can also use :
  =20
  do
  {=20
  /* ... */
  }while(!feof(filePtr));
  =20
  In this way you gain one less check for end of file (where performance =
is important).
  =20
  =20
  About the second read of the "same data" at the end:
  =20
  This happens because the end of file is true only after a failed =
attempt (because the end of file has been already reached and it has no =
more to read). That means it doesn't read the data for the second time, =
but you have a failed attempt to read more data.
    As for the counter you can either decrease it by one after the loop =
or initialize it with -1.
  =20
  =20
  Ioannis
  =20
  * Ioannis Vranos
  * Programming pages: http://members.nbci.com/noicys
  * Alternative URL: http://run.to/noicys
    -----Original Message-----
    From: dev...@li... =
[mailto:dev...@li...]On Behalf Of Sam
    Sent: Saturday, March 17, 2001 8:01 PM
    To: dev...@li...
    Subject: [Dev-C++] feof question


    I'm trying to read through a file using the following statement:

    while(!feof(filePtr)
    {
       fread(&phone, sizeof(struct record), 1, filePtr);
       printf("%d%s", int, name);
       count++;
    }

    The problem is that it reads the last record twice and increments =
the count one more time than needed.  Could someone explain why this =
happens and how to avoid it using the feof function?  Thanks.

    Sam

Re: [Dev-C++] feof question

[BoB S. <squ...@ya...>]

     I believe it is because C++ encounters the eof
marker AFTER it tries to read past the last item in
the file. Therefore you should be testing for the eof
after u read from the file each time rather than
before.  Correct me if im wrong anyone please.

Sev
--- Sam <sch...@ho...> wrote:
> I'm trying to read through a file using the
> following statement:
> 
> while(!feof(filePtr)
> {
>    fread(&phone, sizeof(struct record), 1, filePtr);
>    printf("%d%s", int, name);
>    count++;
> }
> 
> The problem is that it reads the last record twice
> and increments the count one more time than needed. 
> Could someone explain why this happens and how to
> avoid it using the feof function?  Thanks.
> 
> Sam
> 


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