Reading words from a text file

[mattia]

I've came up with this:

FILE *fd;
char buf[100];
char fmt[10];

/* open fd */
sprintf(fmt, "%%%ds", sizeof(buf)-1);
while (fscanf(fd, fmt, buf) != EOF)
use_word(strdup (buf));

close(fd);

Is it the best way? What do you think?
Thanks,
Mattia

[Ben Bacarisse]

Re: Reading words from a text file

mattia <gervaz@gmail.c omwrites:

I've came up with this:
>
FILE *fd;
char buf[100];
char fmt[10];
>
/* open fd */
sprintf(fmt, "%%%ds", sizeof(buf)-1);
while (fscanf(fd, fmt, buf) != EOF)
use_word(strdup (buf));
>
close(fd);
>
Is it the best way? What do you think?

Define "best"?! It is one way (I'd test fscanf(...) == 1 rather != EOF
but that is a small matter) but only you know if it is the best for
your purpose.

You can embed macro into a format string using the # operator and
string literal concatenation ("%" "32" "s" is the same literal as
"%32s"). But that requires an extra function-like macro and adding 1
when the macro is used to define the array. I think the details are
in the FAQ.

Personally, I'd just write a 'int get_word(FILE *fp, char *buf, size_t
size);' function. It is not hard, and you'll use it 1000 (and
re-write it 10) times before you retire. It is odd, but C seems to
encourage this sort of build your own private tool-kit approach.

--
Ben.

[Eric Sosman]

Re: Reading words from a text file

mattia wrote:

I've came up with this:
>
FILE *fd;
char buf[100];
char fmt[10];
>
/* open fd */
sprintf(fmt, "%%%ds", sizeof(buf)-1);
while (fscanf(fd, fmt, buf) != EOF)
use_word(strdup (buf));
>
close(fd);
>
Is it the best way? What do you think?

You shouldn't use "%d" with a size_t value and you
should use fclose instead of close, but those are easily
fixed. I'd worry about the (non-Standard) strdup function
returning a NULL, and I'd probably write use_word(buf) and
leave it up to use_word to decide whether to make a copy,
but that's probably not what you're asking about.

An alternative (I don't say it's better or worse, just
that there are other ways):

#define MAXWORD 99
#define STRING(x) STRING_HELPER(x )
#define STRING_HELPER(x ) #x
...
char buf[MAXWORD+1];
while (fscanf(fd, "%" STRING(MAXWORD) "s", buf) != EOF)
...

--
Eric Sosman
esosman@ieee-dot-org.invalid

[mattia]

Re: Reading words from a text file

On Wed, 09 Apr 2008 08:29:07 -0400, Eric Sosman wrote:

mattia wrote:

>I've came up with this:
>>
>FILE *fd;
>char buf[100];
>char fmt[10];
>>
>/* open fd */
>sprintf(fmt, "%%%ds", sizeof(buf)-1); while (fscanf(fd, fmt, buf) !=
>EOF)
> use_word(strdup (buf));
>>
>close(fd);
>>
>Is it the best way? What do you think?

>
You shouldn't use "%d" with a size_t value and you
should use fclose instead of close, but those are easily fixed. I'd
worry about the (non-Standard) strdup function returning a NULL, and I'd
probably write use_word(buf) and leave it up to use_word to decide
whether to make a copy, but that's probably not what you're asking
about.
>
An alternative (I don't say it's better or worse, just
that there are other ways):
>
#define MAXWORD 99
#define STRING(x) STRING_HELPER(x )
#define STRING_HELPER(x ) #x
...
char buf[MAXWORD+1];
while (fscanf(fd, "%" STRING(MAXWORD) "s", buf) != EOF)
...

Great, I'll use this trick, thanks.

--
__mattia__

[stdazi@gmail.com]

Re: Reading words from a text file

I just hope you free the reference to the string in use_word
On Apr 9, 12:14 pm, mattia <ger...@gmail.c omwrote:

I've came up with this:
>
FILE *fd;
char buf[100];
char fmt[10];
>
/* open fd */
sprintf(fmt, "%%%ds", sizeof(buf)-1);
while (fscanf(fd, fmt, buf) != EOF)
        use_word(strdup (buf));
>
close(fd);
>
Is it the best way? What do you think?
Thanks,
Mattia

[Barry Schwarz]

Re: Reading words from a text file

On 09 Apr 2008 13:21:21 GMT, mattia <gervaz@gmail.c omwrote:

>On Wed, 09 Apr 2008 08:29:07 -0400, Eric Sosman wrote:
>

>mattia wrote:

>>I've came up with this:
>>>
>>FILE *fd;
>>char buf[100];
>>char fmt[10];
>>>
>>/* open fd */
>>sprintf(fmt , "%%%ds", sizeof(buf)-1); while (fscanf(fd, fmt, buf) !=
>>EOF)
>> use_word(strdup (buf));
>>>
>>close(fd);
>>>
>>Is it the best way? What do you think?

>>
> You shouldn't use "%d" with a size_t value and you
>should use fclose instead of close, but those are easily fixed. I'd
>worry about the (non-Standard) strdup function returning a NULL, and I'd
>probably write use_word(buf) and leave it up to use_word to decide
>whether to make a copy, but that's probably not what you're asking
>about.
>>
> An alternative (I don't say it's better or worse, just
>that there are other ways):
>>
> #define MAXWORD 99
> #define STRING(x) STRING_HELPER(x )
> #define STRING_HELPER(x ) #x
> ...
> char buf[MAXWORD+1];
> while (fscanf(fd, "%" STRING(MAXWORD) "s", buf) != EOF)
> ...

>
>Great, I'll use this trick, thanks.

You do realize that any use of *scanf to read a string will stop at
the first white space character. Since you mentioned a function
called use_word, maybe you really do want to stop at the space that
terminates the current word.

However if you want to read a string that contains embedded blanks,
you may find fgets more suitable.


Remove del for email

[mattia]

Re: Reading words from a text file

On Wed, 09 Apr 2008 08:20:44 -0700, Barry Schwarz wrote:

On 09 Apr 2008 13:21:21 GMT, mattia <gervaz@gmail.c omwrote:
>

>>On Wed, 09 Apr 2008 08:29:07 -0400, Eric Sosman wrote:
>>

>>mattia wrote:
>>>I've came up with this:
>>>>
>>>FILE *fd;
>>>char buf[100];
>>>char fmt[10];
>>>>
>>>/* open fd */
>>>sprintf(fm t, "%%%ds", sizeof(buf)-1); while (fscanf(fd, fmt, buf) !=
>>>EOF)
>>> use_word(strdup (buf));
>>>>
>>>close(fd);
>>>>
>>>Is it the best way? What do you think?
>>>
>> You shouldn't use "%d" with a size_t value and you
>>should use fclose instead of close, but those are easily fixed. I'd
>>worry about the (non-Standard) strdup function returning a NULL, and
>>I'd probably write use_word(buf) and leave it up to use_word to decide
>>whether to make a copy, but that's probably not what you're asking
>>about.
>>>
>> An alternative (I don't say it's better or worse, just
>>that there are other ways):
>>>
>> #define MAXWORD 99
>> #define STRING(x) STRING_HELPER(x )
>> #define STRING_HELPER(x ) #x
>> ...
>> char buf[MAXWORD+1];
>> while (fscanf(fd, "%" STRING(MAXWORD) "s", buf) != EOF)
>> ...

>>
>>Great, I'll use this trick, thanks.

>
You do realize that any use of *scanf to read a string will stop at the
first white space character. Since you mentioned a function called
use_word, maybe you really do want to stop at the space that terminates
the current word.
>
However if you want to read a string that contains embedded blanks, you
may find fgets more suitable.
>
>
Remove del for email

Actually I've got to read the words used in /usr/share/dict/words



--
__mattia__

[mattia]

Re: Reading words from a text file

On Wed, 09 Apr 2008 08:10:43 -0700, stdazi@gmail.co m wrote:

I just hope you free the reference to the string in use_word On Apr 9,
12:14 pm, mattia <ger...@gmail.c omwrote:

>I've came up with this:
>>
>FILE *fd;
>char buf[100];
>char fmt[10];
>>
>/* open fd */
>sprintf(fmt, "%%%ds", sizeof(buf)-1); while (fscanf(fd, fmt, buf) !=
>EOF)
>        use_word(strdup (buf));
>>
>close(fd);
>>
>Is it the best way? What do you think? Thanks,
>Mattia

Hmn, actually no, maybe it is better if I call use_word(buf) and then
decide to copy the buffer using strdup(), then I'll free the pointer
returned.



--
__mattia__

[CBFalconer]

Re: Reading words from a text file

Barry Schwarz wrote:

mattia <gervaz@gmail.c omwrote:

>Eric Sosman wrote:

>>mattia wrote:
>>>
>>>I've came up with this:
>>>>
>>>FILE *fd;
>>>char buf[100];
>>>char fmt[10];
>>>>
>>>/* open fd */
>>>sprintf(fm t, "%%%ds", sizeof(buf)-1);
>>>while (fscanf(fd, fmt, buf) != EOF)
>>> use_word(strdup (buf));
>>>>
>>>close(fd);
>>>>
>>>Is it the best way? What do you think?
>>>
>>You shouldn't use "%d" with a size_t value and you should use
>>fclose instead of close, but those are easily fixed. I'd worry
>>about the (non-Standard) strdup function returning a NULL, and
>>I'd probably write use_word(buf) and leave it up to use_word to
>>decide whether to make a copy, but that's probably not what
>>you're asking about.
>>>
>>An alternative (I don't say it's better or worse, just
>>that there are other ways):
>>>
>> #define MAXWORD 99
>> #define STRING(x) STRING_HELPER(x )
>> #define STRING_HELPER(x ) #x
>> ...
>> char buf[MAXWORD+1];
>> while (fscanf(fd, "%" STRING(MAXWORD) "s", buf) != EOF)
>> ...

>>
>Great, I'll use this trick, thanks.

>
You do realize that any use of *scanf to read a string will stop
at the first white space character. Since you mentioned a
function called use_word, maybe you really do want to stop at
the space that terminates the current word.
>
However if you want to read a string that contains embedded
blanks, you may find fgets more suitable.

He might consider using ggets() instead, which returns an allocated
buffer that you can use until you 'free' it. Written in standard C,
and fully portable. See:

<http://cbfalconer.home .att.net/download/>

--
[mail]: Chuck F (cbfalconer at maineline dot net)
[page]: <http://cbfalconer.home .att.net>
Try the download section.


** Posted from http://www.teranews.com **

[mattia]

Re: Reading words from a text file

On Wed, 09 Apr 2008 21:07:40 -0400, CBFalconer wrote:

Barry Schwarz wrote:

>mattia <gervaz@gmail.c omwrote:

>>Eric Sosman wrote:
>>>mattia wrote:
>>>>
>>>>I've came up with this:
>>>>>
>>>>FILE *fd;
>>>>char buf[100];
>>>>char fmt[10];
>>>>>
>>>>/* open fd */
>>>>sprintf(fmt , "%%%ds", sizeof(buf)-1); while (fscanf(fd, fmt, buf) !=
>>>>EOF)
>>>> use_word(strdup (buf));
>>>>>
>>>>close(fd) ;
>>>>>
>>>>Is it the best way? What do you think?
>>>>
>>>You shouldn't use "%d" with a size_t value and you should use fclose
>>>instead of close, but those are easily fixed. I'd worry about the
>>>(non-Standard) strdup function returning a NULL, and I'd probably
>>>write use_word(buf) and leave it up to use_word to decide whether to
>>>make a copy, but that's probably not what you're asking about.
>>>>
>>>An alternative (I don't say it's better or worse, just that there are
>>>other ways):
>>>>
>>> #define MAXWORD 99
>>> #define STRING(x) STRING_HELPER(x )
>>> #define STRING_HELPER(x ) #x
>>> ...
>>> char buf[MAXWORD+1];
>>> while (fscanf(fd, "%" STRING(MAXWORD) "s", buf) != EOF)
>>> ...
>>>
>>Great, I'll use this trick, thanks.

>>
>You do realize that any use of *scanf to read a string will stop at the
>first white space character. Since you mentioned a function called
>use_word, maybe you really do want to stop at the space that terminates
>the current word.
>>
>However if you want to read a string that contains embedded blanks, you
>may find fgets more suitable.

>
He might consider using ggets() instead, which returns an allocated
buffer that you can use until you 'free' it. Written in standard C, and
fully portable. See:
>
<http://cbfalconer.home .att.net/download/>

Great, thanks.



--
Mattia