strtok

[sjgriffiths]

hello

I have the following

while(fgets(b2b_rates_address,1000,in_fp) != NULL )
{    
     strcpy(rates_details[j].ig1, strtok(b2b_rates_address,","));
     printf("rates_details[j].ig7 = %s\n",rates_details[j].ig1 );
     strcpy(rates_details[j].ig2,strtok(NULL,","));
     printf("rates_details[j].ig7 = %s\n",rates_details[j].ig2 );
     strcpy(rates_details[j].ig3,strtok(NULL,","));
     printf("rates_details[j].ig7 = %s\n",rates_details[j].ig3 );
     j++;
}

The issue i have is this:-
It works fine up to field ig3, this is due to the fact that this field may/may not be empty....the program then bombs out

How can I get round this? any code examples would be appreciated

Many Thanks

[Ancient Dragon]

You are not validating the return value of strtok(). It returns NULL if its at the end of the string when you call strtok() with a NULL first parameter (or some other error occurred). It would be more prudent to code it like this:

char* ptr;
while(fgets(b2b_rates_address,1000,in_fp) != NULL )
{
     if( (ptr = strtok(b2b_rates_address,","))
     {
            strcpy(rates_details[j].ig1, ptr);
            printf("rates_details[j].ig7 = %s\n",rates_details[j].ig1 );
            if( (ptr = strtok(NULL,",") )
            {
                  strcpy(rates_details[j].ig2,ptr);
                  printf("rates_details[j].ig7 = %s\n",rates_details[j].ig2 );
                  if( (ptr = strtok(NULL, ","))
                  {
                      strcpy(rates_details[j].ig3, ptr);
                      printf("rates_details[j].ig7 = %s\n",rates_details[j].ig3 );
                   }
           }
     }
     j++;
}

[Narue]

>this field may/may not be empty
strtok ignores empty fields, so if that field is empty, you're actually processing a null pointer because there are fewer fields than you're expecting. If you want to get an empty string for the empty field, don't use strtok.