file access - design thoughts.

[J.Broeden]

Hi, I'm hoping to get some advice on this design query to see if I'm
heading in the right direction.

I would like to read a file of many lines and then search for a
particular character to break up the sentence into separate words.
Once done I will sort them.

I thought of using fgets but the line could be very very long and I
won't know it's length of n characters that could be in a line.

Using fgetc seems the better bet and put each character into an array
so I can traverse the array.

However,if I put each character into an array, I still won't know how
large to make the array.

Is there a better strategy ?

Jay

[Ian Collins]

J.*******@gmail .com wrote:

Hi, I'm hoping to get some advice on this design query to see if I'm
heading in the right direction.

I would like to read a file of many lines and then search for a
particular character to break up the sentence into separate words.
Once done I will sort them.

I thought of using fgets but the line could be very very long and I
won't know it's length of n characters that could be in a line.

Using fgetc seems the better bet and put each character into an array
so I can traverse the array.

However,if I put each character into an array, I still won't know how
large to make the array.

Is there a better strategy ?

If portability isn't an issue, you will probably be better of using your
operating system's means of memory mapping the file and simply using the
result as an array.

--
Ian Collins.

[Malcolm McLean]

<J.*******@gmai l.comwrote in message
news:11******** *************@w 5g2000hsg.googl egroups.com...

Hi, I'm hoping to get some advice on this design query to see if I'm
heading in the right direction.

I would like to read a file of many lines and then search for a
particular character to break up the sentence into separate words.
Once done I will sort them.

I thought of using fgets but the line could be very very long and I
won't know it's length of n characters that could be in a line.

Using fgetc seems the better bet and put each character into an array
so I can traverse the array.

However,if I put each character into an array, I still won't know how
large to make the array.

Is there a better strategy ?

Google for ggets and Chuck Falconer.
Chuck, a reg in this group, has kindly provided exactly what you want. I
believe entirely rights free, certainly for nothing.

[pete]

J.*******@gmail .com wrote:

>
Hi, I'm hoping to get some advice on this design query to see if I'm
heading in the right direction.

I would like to read a file of many lines and then search for a
particular character to break up the sentence into separate words.
Once done I will sort them.

I thought of using fgets but the line could be very very long and I
won't know it's length of n characters that could be in a line.

Using fgetc seems the better bet and put each character into an array
so I can traverse the array.

However,if I put each character into an array, I still won't know how
large to make the array.

Is there a better strategy ?

get_line uses getc to read lines, and realloc to size the array.
Truncates lines at (size_t)-1) bytes.

http://www.mindspring.com/~pfilandr/...ine/get_line.c

--
pete

[Tor Rustad]

J.*******@gmail .com wrote:

Hi, I'm hoping to get some advice on this design query to see if I'm
heading in the right direction.

I would like to read a file of many lines and then search for a
particular character to break up the sentence into separate words.
Once done I will sort them.

I thought of using fgets but the line could be very very long and I
won't know it's length of n characters that could be in a line.

Your problem, is well known for compiler writers, they call it lexical
analysis. fgets() is not normally used in hand-written lexer's, but
getchar() and ungetc() is, because you analyze single character at a time.

Using fgetc seems the better bet and put each character into an array
so I can traverse the array.

However,if I put each character into an array, I still won't know how
large to make the array.

Is there a better strategy ?

Yes, there is standard tool for this, called lex. Here is a lex
specification that print all the words in a file:

$ cat ex_lex.l
/*
Compile:
flex ex_lex.l
cc lex.yy.c -ll

Run:
../a.out < ex_lex.l
*/

%{
%}
%%

[^ \n\t]+ { printf("Word: '%s', len = %d\n", yytext, yyleng); }
..|\n ; /* ignore anything else */

%%

int main(void)
{
yylex();
}

--
Tor <torust [at] online [dot] no>

[CBFalconer]

Malcolm McLean wrote:

<J.*******@gmai l.comwrote in message

>Hi, I'm hoping to get some advice on this design query to see if I'm
heading in the right direction.

I would like to read a file of many lines and then search for a
particular character to break up the sentence into separate words.
Once done I will sort them.

I thought of using fgets but the line could be very very long and I
won't know it's length of n characters that could be in a line.

Using fgetc seems the better bet and put each character into an array
so I can traverse the array.

However,if I put each character into an array, I still won't know how
large to make the array.

Is there a better strategy ?

Google for ggets and Chuck Falconer.
Chuck, a reg in this group, has kindly provided exactly what you want.
I believe entirely rights free, certainly for nothing.

try: <http://cbfalconer.home .att.net/download/>
--
<http://www.cs.auckland .ac.nz/~pgut001/pubs/vista_cost.txt>
<http://www.securityfoc us.com/columnists/423>
<http://www.aaxnet.com/editor/edit043.html>
<http://kadaitcha.cx/vista/dogsbreakfast/index.html>
cbfalconer at maineline dot net
--
Posted via a free Usenet account from http://www.teranews.com

[CBFalconer]

Tor Rustad wrote:

J.*******@gmail .com wrote:

.... SNIP ...

>>
I would like to read a file of many lines and then search for a
particular character to break up the sentence into separate words.
Once done I will sort them.

I thought of using fgets but the line could be very very long and I
won't know it's length of n characters that could be in a line.

Your problem, is well known for compiler writers, they call it lexical
analysis. fgets() is not normally used in hand-written lexer's, but
getchar() and ungetc() is, because you analyze single character at a time.

>Using fgetc seems the better bet and put each character into an array
so I can traverse the array.

However,if I put each character into an array, I still won't know how
large to make the array.

Is there a better strategy ?

Yes, there is standard tool for this, called lex. Here is a lex
specification that print all the words in a file:

$ cat ex_lex.l
/*
Compile:
flex ex_lex.l
cc lex.yy.c -ll

Run:
./a.out < ex_lex.l
*/

%{
%}
%%

[^ \n\t]+ { printf("Word: '%s', len = %d\n", yytext, yyleng); }
.|\n ; /* ignore anything else */

%%

int main(void)
{
yylex();
}

Why all that tortuous mess to copy text?.

#include <stdio.h>

int main(void) {
int ch;

while (EOF != (ch = getchar())) putchar(ch);
return 0;
}

--
<http://www.cs.auckland .ac.nz/~pgut001/pubs/vista_cost.txt>
<http://www.securityfoc us.com/columnists/423>
<http://www.aaxnet.com/editor/edit043.html>
<http://kadaitcha.cx/vista/dogsbreakfast/index.html>
cbfalconer at maineline dot net

--
Posted via a free Usenet account from http://www.teranews.com

[Tor Rustad]

CBFalconer wrote:

[...]

Why all that tortuous mess to copy text?.

Hand-written lexer in C is easy, but writing a lex spec is easier.

Try again, this time print each *word* and it's length on a separate line on
the output. Please follow your own bogus advice, by using ggets().

--
Tor <torust [at] online [dot] no>

[Malcolm McLean]

"Tor Rustad" <to****@online. nowrote in message
news:ir******** *************@t elenor.com...

CBFalconer wrote:

[...]

>Why all that tortuous mess to copy text?.

Hand-written lexer in C is easy, but writing a lex spec is easier.

Try again, this time print each *word* and it's length on a separate line
on
the output. Please follow your own bogus advice, by using ggets().

Why is ggets() a problem for this task?
Granted les / flex is a dedicated lexical analyser and in its element with
token generation, but most people don't have the inclination to learn yet
another language for such a simple spec.

--
Free games and programming goodies.
http://www.personal.leeds.ac.uk/~bgy1mm

[Tor Rustad]

Malcolm McLean wrote:

>
"Tor Rustad" <to****@online. nowrote in message
news:ir******** *************@t elenor.com...

>CBFalconer wrote:

[...]

>>Why all that tortuous mess to copy text?.

Hand-written lexer in C is easy, but writing a lex spec is easier.

Try again, this time print each *word* and it's length on a separate line
on the output. Please follow your own bogus advice, by using ggets().

Why is ggets() a problem for this task?

OP needed to split the file content into words, not lines! Hence, this is
what he wanted in C:

int lexer(char *word, size_t *wlen)
{
int t;

while (1)
{
t = getchar();

/* Eat white space */
if (t == ' ' || t == '\t' || t == '\n')
;
else if (t == EOF)
return EOF;

etc...
}
}

adding logic to handle lines, just complicate matters. Hence, using fgets(),
ggets(), getline() etc. was all bad advice.

Granted les / flex is a dedicated lexical analyser and in its element with
token generation, but most people don't have the inclination to learn yet
another language for such a simple spec.

OP asked if there was a better strategy, well there is, he can ignore the
line issue and look into using a dedicated tool for such problems.

Since I had already done the complete lex skeleton, all he needed to do, was
really to add that C sorting code. That hardly qualify as learning a new
language. <g>

--
Tor <torust [at] online [dot] no>