Would strtok() be useful for parsing out periods but keeping them? (C)

Question

I am trying to remove all the whitespace in a string that is made out of multiple sentences, but I would also like to keep the periods separate from each of the tokens. Would strtok() still be useful for this or is there another function I should know about?

Answer 1

If you want to know where the periods are, and treat them as separate tokens, then strtok() is not the right function. It zaps the delimiters with nulls; you don't get told which delimiter it found.

You probably need to look at:

• strspn()
• strcspn()
• strpbrk()

You could also look at other questions about strtok() and its alternatives. There are many. strtok() is a dangerous function. You can't afford to use in a function called from another function that is also using strtok(), nor can you afford to call any other function that uses strtok(). You should look up POSIX strtok_r() or Microsoft's strtok_s(); they're safe for use in library functions. You could also look up strsep().

You might find one of these questions useful:

• I need a mix of strtok() and strtok_single()
• Need to know when no data appears between two token separators

And there are many others that could help.

Answer 2

char str[] ="- This. is a s.ample string.";
char * pch;
printf ("Splitting string \"%s\" into tokens:\n",str);
pch = strtok (str," ,-"); //any other tokens you want to use here
while (pch != NULL)
{
  printf ("%s\n",pch);
  pch = strtok (NULL, " ,-");
}