strtok not working in call function

Question

strtok() is crashing. It works in main(), but not in the call function. Please advise me. Thank you.

int checkNumberOfTokens (char* text, char* delimitChar) {

    int numberOfTokens = 0;
    char *t;
    int i;

    printf("Text: %s\n", text);  
    printf("delimitChar: %s\n", delimitChar);

    t = strtok(text, delimitChar);

    for (i=0; t != NULL; i++) {
        printf("token %d is \"%s\"\n", i, t);
        t = strtok(NULL, delimitChar);
        }

        numberOfTokens = i;
        printf("Total number of tokens: %d\n", numberOfTokens);    

        return numberOfTokens;
}




int main()

    char* transitionTable[] = {
                              "NA, NA, NA, NA, NA, NA",
                              "defaultStart, elseOther, 1, 2, 6, NA",

          };

          printf("%s \n", transitionTable[1]);

    char delimitChar[] = ",";

    checkNumberOfTokens (transitionTable[1], delimitChar);

what is the reason for marking this down? – Ursa Major Nov 15 '13 at 23:24 — Ursa Major, Nov 15 '13 at 23:24

score 3 · Answer 1 · answered Nov 15 '13 at 21:57

3

strtok input string has to be writable as strtok modifies the input string. But you are passing a string literal and string literals are non modifiable.

See c-faq on string literals:

http://c-faq.com/decl/strlitinit.html

answered Nov 15 '13 at 21:57

ouah

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Downvoter, could you explain why you downvoted this answer? – ouah Nov 15 '13 at 22:38

score 2 · Answer 2 · answered Nov 15 '13 at 22:12

2

PROBLEM: You're passing in a string literal (read-only); but strtok() expects to be able to modify the string.

SUGGESTION: try strchr() instead of strtok().

EXAMPLE:

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

int
checkNumberOfTokens (char * text, char delimitChar) 
{
  char *s = text;
  int ct = 1;
  if ((s == NULL) || (strlen(s) == 0))
    return 0;

  while ((s = strchr(s, delimitChar))) {
    s++;
    ct++;
  }
  return ct;
}

int main(int argc, char *argv[]) 
{
   int ct = checkNumberOfTokens("ABC,DEF,GEHI", ',');
   printf ("ct=%d\n", ct);
   return 0;
}

answered Nov 15 '13 at 22:12

paulsm4

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what if my delimiter is changed to "+=+"? – Ursa Major Nov 15 '13 at 22:21
Then use [strstr()](http://www.cplusplus.com/reference/cstring/strstr/) ;) – paulsm4 Nov 15 '13 at 22:42
strstr() giving me the residual token, rather than the targeted. How can we emend this? – Ursa Major Nov 16 '13 at 00:39
Hey, Big Bear - did you get everything squared away? If not, what exactly do you mean by "residual token"? Could you post the relevant code, and explain the problem? – paulsm4 Nov 16 '13 at 22:16
1

Thank you, paulsm4. I just solved the issue, and posted the answer. – Ursa Major Nov 17 '13 at 12:13
http://stackoverflow.com/users/1288/bill-the-lizard deleted my answer. – Ursa Major Nov 17 '13 at 19:57
http://stackoverflow.com/users/59303/chrisf deleted my answer. – Ursa Major Nov 18 '13 at 01:46
http://meta.stackexchange.com/questions/28867/what-recourse-do-i-have-if-i-believe-a-moderator-has-abused-his-her-privileges – Ursa Major Nov 18 '13 at 01:55

strtok not working in call function

2 Answers2