strtok exception handling

[Neel]

Hi friends,
I 'm trying to extract values from a lines which are delimited by a
space
eg.
content of string is: "Hello World"

I use strtok to extract "Hello" and "World"

the code I use is

foo=atoi(strtok (data," "));
bar=atoi(strtok (NULL," "));

BUT If in case there's only one word, it gives me Segmentation Fault.
How can I handle this?
I tried try-catch but didnt work.


Can anyone please help me with this issue?
Thanks in advance

[Keith Thompson]

Re: strtok exception handling

Neel <a.k.vora@gmail .comwrites:

I 'm trying to extract values from a lines which are delimited by a
space
eg.
content of string is: "Hello World"
>
I use strtok to extract "Hello" and "World"
>
the code I use is
>
foo=atoi(strtok (data," "));
bar=atoi(strtok (NULL," "));
>
BUT If in case there's only one word, it gives me Segmentation Fault.
How can I handle this?

You'll have to show us a small, complete, compilable program that
demonstrates the problem.

I tried try-catch but didnt work.

Are you use a C++ compiler? comp.lang.c++ is down the hall, second
door on the left.

--
Keith Thompson (The_Other_Keit h) kst-u@mib.org <http://www.ghoti.net/~kst>
Nokia
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

[Ian Collins]

Re: strtok exception handling

Neel wrote:

Hi friends,
I 'm trying to extract values from a lines which are delimited by a
space
eg.
content of string is: "Hello World"
>
I use strtok to extract "Hello" and "World"
>
the code I use is
>
foo=atoi(strtok (data," "));
bar=atoi(strtok (NULL," "));
>
BUT If in case there's only one word, it gives me Segmentation Fault.
How can I handle this?

Ever thought of checking the return value of strtok?

I tried try-catch but didnt work.
>

Well considering C doesn't have try-catch and the descendent language
that does certainly doesn't use them for asynchronous signals, that's
hardly surprising.

--
Ian Collins.

[s0suk3@gmail.com]

Re: strtok exception handling

On Sep 26, 3:21 am, Neel <a.k.vora@gmail .comwrote:

Hi friends,
I 'm trying to extract values from a lines which are delimited by a
space
eg.
content of string is: "Hello World"
>
I use strtok to extract "Hello" and "World"
>
the code I use is
>
foo=atoi(strtok (data," "));
bar=atoi(strtok (NULL," "));
>
BUT If in case there's only one word, it gives me Segmentation Fault.

Sure, if it's only one word it will return NULL on the second call.

How can I handle this?
I tried try-catch but didnt work.
>

LOL! Did you try something like

try {
foo = atoi(strtok(dat a, " "));
}
catch (SegmentationFa ult e) {
printf("I caught a segfault! :-)\n");
}

Sebastian

[Neel]

Re: strtok exception handling

It gives some error.
Do I need to include any special header file for that?

[Ian Collins]

Re: strtok exception handling

Neel wrote:

It gives some error.
Do I need to include any special header file for that?

Including the context you are replying to in your posts would be a good
start.

--
Ian Collins.

[user923005]

Re: strtok exception handling

On Sep 26, 1:21 am, Neel <a.k.v...@gmail .comwrote:

Hi friends,
I 'm trying to extract values from a lines which are delimited by a
space
eg.
content of string is: "Hello World"
>
I use strtok to extract "Hello" and "World"
>
the code I use is
>
foo=atoi(strtok (data," "));
bar=atoi(strtok (NULL," "));
>
BUT If in case there's only one word, it gives me Segmentation Fault.
How can I handle this?
I tried try-catch but didnt work.

From:

http://www.cplusplus.com/reference/clibrary/cstring/strtok.html

we have this:
/* strtok example */
#include <stdio.h>
#include <string.h>

int main ()
{
char str[] ="- This, a sample string.";
char * pch;
printf ("Splitting string \"%s\" into tokens:\n",str) ;
pch = strtok (str," ,.-");
while (pch != NULL)
{
printf ("%s\n",pch) ;
pch = strtok (NULL, " ,.-");
}
return 0;
}


The while loop is due to this:
Return Value
A pointer to the last token found in string.
A null pointer is returned if there are no tokens left to retrieve.

[Richard Heathfield]

Re: strtok exception handling

Neel said:

Hi friends,
I 'm trying to extract values from a lines which are delimited by a
space
eg.
content of string is: "Hello World"
>
I use strtok to extract "Hello" and "World"
>
the code I use is
>
foo=atoi(strtok (data," "));
bar=atoi(strtok (NULL," "));
>
BUT If in case there's only one word, it gives me Segmentation Fault.
How can I handle this?

By taking advantage of the fact that strtok returns NULL if no more tokens
exist.

p = strtok(data, " ");
if(p != NULL)
{
/* okay, got a token, keep going */
foo = strtol(p, &endptr, 10);
if(endptr p)
{
/* okay, foo populated - keep going */
p = strtok(NULL, " ");
if(p != NULL)
{
/* okay, got a token, keep going */
bar = strtol(p, &endptr, 10);
if(endptr p)
{
/* okay, bar populated, keep going */

[James Kuyper]

Re: strtok exception handling

Neel wrote:

It gives some error.
Do I need to include any special header file for that?

A very special one, I think - it was meant as a joke. The point is that
C doesn't have try/catch. C++ does, and for questions about C++ you
should go to comp.lang.c++. However, I can tell you what their answer
would be: C++ exceptions are also not usable for this purpose.

On the other hand, when strtok() has reached the end of the string you
asked it to tokenize, it returns a null pointer value. You're supposed
to use that fact to decide what to do next. If you try to actually use
that value as if it points to a string (for instance, by passing it to
atoi()), then you're going to get trouble.