trim function dumping core

[rkk]

Hi,

I've written a small trim function to trim away the whitespaces in a
given string. It works well with solaris forte cc compiler, but on
mingw/cygwin gcc it isn't. Here is the code:

char *trim(char *s)
{
char *begin,*end;
begin = s;
/* ltrim start */
while(*begin != '\0') {
if(isspace(*beg in)) {
begin++;
} else {
s = begin;
break;
}
}
/* ltrim end */

/* rtrim start */
end = s + strlen(s) -1;
while( end !=s && isspace(*end) ) {
end--;
}
printf("%c\n",* end);
*(end+1) = '\0';
while(*s && isspace(*s)) s++;
/* rtrim end */
return s;
}

It is failing in the line having the code *(end+1) = '\0';. I think it
may be due to portablility issues & I need this code to work on all
well known platforms & compilers. Any sugesstions/help please?

Thank you.

Regards
Kalyan

[trm]

Fred Kleinschmidt schrieb:

"Chris Dollin" <ch**********@h p.comwrote in message
news:el******** **@murdoch.hpl. hp.com...

Here's my effort, which I offer as a target ...

#include <stdio.h>
#include <ctype.h>

char *trim( char *s )
{
char *lastNonSpace = 0;
char *current;
while (isspace( *s )) s += 1;
current = s;
while (*current)
{
if (!isspace( *current )) lastNonSpace = current;
current += 1;
}
if (lastNonSpace) lastNonSpace[1] = 0;
return s;
}

What happens here?

int main( int argc, char **argv ) {
fprintf( stderr, "'%s'\n", trim(NULL) );
return 0;
}

What happens here?

#include <string.h>
int main ( void )
{
strlen(NULL);
return 0;
}

[santosh]

trm wrote:

What happens here?

#include <string.h>
int main ( void )
{
strlen(NULL);
return 0;
}

Possibly anything. It invokes undefined behaviour.

[CBFalconer]

Chris Dollin wrote:

rkk wrote:

>Chris Dollin wrote:

(fx:snip)

>>#include <stdio.h>
#include <ctype.h>

char *trim( char *s )

(fx:snip more)

>This code doesn't work on my machine. Seems to be broken somewhere.

Hell's teeth, man, can't you be more explicit? What were the
symptoms? What implementation are you using? What, if any,
were the compiler messages? What was the output? Did you compile
the code exactly as I posted it?

If there's a mistake in it, I'd like to know where, but since
my crystal ball is back being repaired right now, I don't
know where to start ...

Seems to work fine here.

--
Chuck F (cbfalconer at maineline dot net)
Available for consulting/temporary embedded and systems.
<http://cbfalconer.home .att.net>

[Richard Heathfield]

santosh said:

trm wrote:

>What happens here?

#include <string.h>
int main ( void )
{
strlen(NULL);
return 0;
}

Possibly anything. It invokes undefined behaviour.

And what happens if someone asks a rhetorical question in comp.lang.c?

--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
email: rjh at the above domain, - www.

[Richard Tobin]

In article <8_************ ********@bt.com >,
Richard Heathfield <rj*@see.sig.in validwrote:

>And what happens if someone asks a rhetorical question in comp.lang.c?

I don't think it's ever happened, has it?

-- Richard
--
"Considerat ion shall be given to the need for as many as 32 characters
in some alphabets" - X3.4, 1963.

[santosh]

Richard Heathfield wrote:

santosh said:

trm wrote:

What happens here?

#include <string.h>
int main ( void )
{
strlen(NULL);
return 0;
}

Possibly anything. It invokes undefined behaviour.

And what happens if someone asks a rhetorical question in comp.lang.c?

Damn! I should stop taking myself so seriously.

[Keith Thompson]

Richard Heathfield <rj*@see.sig.in validwrites:
[...]

And what happens if someone asks a rhetorical question in comp.lang.c?

Some idiot invariably answers it.

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <* <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

[christian.bau]

rkk wrote:

Hi,

I've written a small trim function to trim away the whitespaces in a
given string. It works well with solaris forte cc compiler, but on
mingw/cygwin gcc it isn't. Here is the code:

char *trim(char *s)
{
char *begin,*end;
begin = s;
/* ltrim start */
while(*begin != '\0') {
if(isspace(*beg in)) {
begin++;
} else {
s = begin;
break;
}
}
/* ltrim end */

/* rtrim start */
end = s + strlen(s) -1;
while( end !=s && isspace(*end) ) {
end--;
}
printf("%c\n",* end);
*(end+1) = '\0';
while(*s && isspace(*s)) s++;
/* rtrim end */
return s;
}

There are no compatibility issues, the code is just plainly broken.
Have a careful look what happens when you pass in an empty string.

[Joe Wright]

rkk wrote:

Hi,

I've written a small trim function to trim away the whitespaces in a
given string. It works well with solaris forte cc compiler, but on
mingw/cygwin gcc it isn't. Here is the code:

char *trim(char *s)
{
char *begin,*end;
begin = s;
/* ltrim start */
while(*begin != '\0') {
if(isspace(*beg in)) {
begin++;
} else {
s = begin;
break;
}
}
/* ltrim end */

/* rtrim start */
end = s + strlen(s) -1;
while( end !=s && isspace(*end) ) {
end--;
}
printf("%c\n",* end);
*(end+1) = '\0';
while(*s && isspace(*s)) s++;
/* rtrim end */
return s;
}

It is failing in the line having the code *(end+1) = '\0';. I think it
may be due to portablility issues & I need this code to work on all
well known platforms & compilers. Any sugesstions/help please?

Here's mine..

/*************** *************** *************** *************** ********
Program: trim.c
Author: Joe Wright
Date: 12/06/2006

rtrim() and ltrim() functions a la dBASE modify string in place.

*************** *************** *************** *************** *********/

#include <stdio.h>
#include <string.h>
#include <ctype.h>

#define length 256 /* Limit lines to 255 characters */
#define trim rtrim /* trim() is synonomous with rtrim() */

/* Remove trailing whitespace */

char * rtrim(char *str) {
char *s, *p; int c;
s = p = str;
while ((c = *s++)) if (!isspace(c)) p = s;
*p = '\0';
return str;
}

/* Remove leading whitespace */

char * ltrim(char *str) {
char *s, *p;
for (s = p = str; *s && isspace(*s); s++) ;
while ((*p++ = *s++)) ;
return str;
}

/* Combination of the two */

char * alltrim(char *str) {
return rtrim(ltrim(str ));
}

/* A modest test */

int main(int argc, char **argv) {
char str[length];

if (argc != 2) {
printf("Usage: trim ' Try something like this. '\n");
return 0;
}

if (strlen(argv[1]) length-1) {
printf("Input String Too Long!\n");
return 0;
}
strcpy(str, argv[1]);
printf(" Input: Length %2d '%s'\n", (int)strlen(str ), str);

ltrim(str);
printf(" ltrim: Length %2d '%s'\n", (int)strlen(str ), str);

strcpy(str, argv[1]);
rtrim(str);
printf(" rtrim: Length %2d '%s'\n", (int)strlen(str ), str);

strcpy(str, argv[1]);
alltrim(str);
printf("alltrim : Length %2d '%s'\n", (int)strlen(str ), str);

return 0;
}
/* End of trim.c */
--
Joe Wright
"Everything should be made as simple as possible, but not simpler."
--- Albert Einstein ---

[rkk]

All,

Thank you for your code snippets & help provided. Here is my code which
works on Linux, Solaris & windows:

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define MAX_STR_LEN 4000

char *trim(char *s);
char *rtrim(char *s);
char *ltrim(char *s);

char *trim(char *s)
{
char t[MAX_STR_LEN];
char *begin,*end;
strcpy(t,s);
begin = t;

while(*begin != '\0') {
if(isspace(*beg in)) begin++;
else {
strcpy(t , begin);
break;
}
}

end = t + strlen(t) - 1;
while(end != t && isspace(*end)) end--;
*(end + 1) = '\0';
s = t;

return s;
}

char *ltrim(char *s)
{
char *begin;
begin = s;
while(*begin != '\0') {
if(isspace(*beg in)) begin++;
else {
s = begin;
break;
}
}
return s;
}

char *rtrim(char *s)
{
char t[MAX_STR_LEN];
char *end;
strcpy(t,s);
end = t + strlen(t) - 1;
while(end != t && isspace(*end)) end--;
*(end + 1) = '\0';
s = t;

return s;
}

int main()
{
char *str = " sample string ";
printf("[%s]\n",str);
printf("ltrim [%s]\n",ltrim(str)) ;
printf("rtrim [%s]\n",rtrim(str)) ;
printf("trim [%s]\n",trim(str) );

return 0;
}
Thanks & Regards
RKK

On Dec 7, 6:19 am, Joe Wright <joewwri...@com cast.netwrote:

rkk wrote:

Hi,

I've written a small trim function to trim away the whitespaces in a
given string. It works well with solaris forte cc compiler, but on
mingw/cygwin gcc it isn't. Here is the code:

char *trim(char *s)
{
char *begin,*end;
begin = s;
/* ltrim start */
while(*begin != '\0') {
if(isspace(*beg in)) {
begin++;
} else {
s = begin;
break;
}
}
/* ltrim end */

/* rtrim start */
end = s + strlen(s) -1;
while( end !=s && isspace(*end) ) {
end--;
}
printf("%c\n",* end);
*(end+1) = '\0';
while(*s && isspace(*s)) s++;
/* rtrim end */
return s;
}

It is failing in the line having the code *(end+1) = '\0';. I think it
may be due to portablility issues & I need this code to work on all
well known platforms & compilers. Any sugesstions/help please?Here's mine..

/*************** *************** *************** *************** ********
Program: trim.c
Author: Joe Wright
Date: 12/06/2006

rtrim() and ltrim() functions a la dBASE modify string in place.

*************** *************** *************** *************** *********/

#include <stdio.h>
#include <string.h>
#include <ctype.h>

#define length 256 /* Limit lines to 255 characters */
#define trim rtrim /* trim() is synonomous with rtrim() */

/* Remove trailing whitespace */

char * rtrim(char *str) {
char *s, *p; int c;
s = p = str;
while ((c = *s++)) if (!isspace(c)) p = s;
*p = '\0';
return str;

}/* Remove leading whitespace */

char * ltrim(char *str) {
char *s, *p;
for (s = p = str; *s && isspace(*s); s++) ;
while ((*p++ = *s++)) ;
return str;

}/* Combination of the two */

char * alltrim(char *str) {
return rtrim(ltrim(str ));

}/* A modest test */

int main(int argc, char **argv) {
char str[length];

if (argc != 2) {
printf("Usage: trim ' Try something like this. '\n");
return 0;
}

if (strlen(argv[1]) length-1) {
printf("Input String Too Long!\n");
return 0;
}
strcpy(str, argv[1]);
printf(" Input: Length %2d '%s'\n", (int)strlen(str ), str);

ltrim(str);
printf(" ltrim: Length %2d '%s'\n", (int)strlen(str ), str);

strcpy(str, argv[1]);
rtrim(str);
printf(" rtrim: Length %2d '%s'\n", (int)strlen(str ), str);

strcpy(str, argv[1]);
alltrim(str);
printf("alltrim : Length %2d '%s'\n", (int)strlen(str ), str);

return 0;}/* End of trim.c */

--
Joe Wright
"Everything should be made as simple as possible, but not simpler."
--- Albert Einstein ---