qsort an array of strings, compare

Question

I am trying to figure out how to use qsort with an array of strings. My code looks like this.

char words[500][256];

int numOfWords; // this is calculated above

int sortWordList() {
    int length = sizeof(words) / sizeof(char *);
    qsort(words, length, sizeof(char*), compare);

}

int compare (const void * a, const void * b ) {
    const char *pa = *(const char**)a;
    const char *pb = *(const char**)b;

    return strcmp(pa,pb);
}

However, I get a "Access violation reading location 0x###.." everytime and I dont know whats wrong. Can anyone spot my problem?

EDIT: Thanks for the wonderful help. You guys are always the best.

Hint: a two-dimensional array of char is not the same as an array of pointers to char. — zwol
– zwol, Commented Apr 25, 2014 at 20:30

tcollart · Accepted Answer · 2014-04-25 20:33:35Z

1

You are not casting your const void * to const char * properly, to do so, use instead:

const char *pa = (const char *)a;
const char *pb = (const char *)b;

Plus compare() should be above sortWordList() as you're using it in sortWordList().

answered Apr 25, 2014 at 20:33

tcollart

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1 Comment

RestlessAPI Over a year ago

OK, so now the list gets sorted, but if I only have 90 elements in the list, the last 410 elements of empty space show up first. Is there a way to have my data show up first? (FIXED).

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