is there an easier way?

[Tim Daneliuk]

Tim Daneliuk wrote:
> Tim Daneliuk wrote:
>> Gary Kline wrote:
>>>     To my fellow C nerds,
>>>
>>>     It's been a  great manny years since I wrote this appended
>>>     snippet.  Now I can't remember why (of if ) I need all the
>>>     strcpy() calls.   Is there a simpler, more logical way of     
>>> printing a bunch of string by snipping off the left-most?
>>>
>>>     In short,, can anyone 'splain why strtok needs all this?
>>>
>>>     tia,
>>>
>>>     gary
>>>
>>>
>>
>> I don't think you need the copies.  This works just as well:
>>
>> #include <stdio.h>
>> #include <string.h>
>>
>> main()
>> {
>>   char *bp, *tok;
>>   char *delim=" ", s1[256]="abc def ghi jkl mno.";
>>
>>   bp = s1;   /* Now both point to the literal string to be tokenized */
>>
>>   while ((tok = strtok(bp, delim)) != NULL)
>>   {
>>     bp = NULL;
>>     printf("tok = [%s]\n", tok);
>>   }
>> }
>>
> 
> 
> Ooops ... wasn't paying attention.  While the printed output is the 
> same, doing
> it this way is destructive to the original s1 string - which may matter 
> (or not)...

So, to protect the original string, you do have to copy the original
string to a new buffer:


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

main()
{
   char *bp, *tok, buf[256];
   const char *delim=" ", s1[256]="abc def ghi jkl mno.";

   bp = strcpy(buf, s1);

   while ((tok = strtok(bp, delim)) != NULL)
   {
     bp = NULL;
     printf("tok = [%s]\n", tok);
   }
}


So, at least we eliminated the first strcpy in your code:

   char *bp, buf[512], *tok, tstr[512];
   static char *delim=" ", s1[256]="abc def ghi jkl mno.";

   bp = strcpy(buf, tstr);

This accomplishes nothing and may not even be safe - strcpy() copies
until it hits \0.  I do not recall if the declaration of tstr[512]
intializes it to \0.  If not, then the strcpy() is going to keep
running until it finds one, overwriting the end of buf[] and probably
causing core dumps or other evil...
-- 
----------------------------------------------------------------------------
Tim Daneliuk     tundra at tundraware.com
PGP Key:         http://www.tundraware.com/PGP/