string array in C with files

Question

I am trying to tokenize a File and insert certain strings into an array. When I tokenize the file and print out each token, it works fine, but when I put each token into an array and print out the contents of the array, the contents are not the same at all.

char *filenames[1000];    
token = strtok(line, " ");              
while (token != NULL) {                     
    printf("%s\n", token);                      
    /*                      
      filenames[i] = token;                     
      i++;                      
    */                      
    token = strtok(NULL, " ");                  
}                   
ck = fgets(line, 1000, fp);    
for (j = 0; j <= i; j++){               
    printf("%s \n", filenames[j]);              
}

Am I supposed to malloc the array of filenames, or malloc each token?

cnicutar · Accepted Answer · 2012-12-05 21:31:49Z

1

You keep reusing the same pointer over and over. Try something like:

filenames[i] = strdup(token);

You should also remember to free(filenames[i]) when you're done with them.

If you don't have strdup you can roll your own or just use:

filenames[i] = malloc(strlen(token) + 1);    /* XXX check malloc return. */
strcpy(filenames[i], token);

answered Dec 5, 2012 at 21:31

cnicutar

184k26 gold badges378 silver badges398 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

user1880514 Over a year ago

Thank You! I used the malloc instead of strdup and it worked. For some reason though, when I tokenize my file, lines are being inserted as tokens even though there are no lines between my words. My file looks like this: <list> filename frequency filename frequency <\list>. and all I want inserted in the filenames array are the unique filenames. The strtok should be tokenizing them by " " but I dont know why the extra lines are being added in as tokens. Any idea why?

Collectives™ on Stack Overflow

string array in C with files

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related