Question

Here are functions on strings from programming pearls.

int wordncmp(char *p, char* q)
{   int n = k;
    for ( ; *p == *q; p++, q++)
        if (*p == 0 && --n == 0)
            return 0;
    return *p - *q;
}

int sortcmp(char **p, char **q)
{   return wordncmp(*p, *q);
}

char *skip(char *p, int n)
{   for ( ; n > 0; p++)
        if (*p == 0)
            n--;
    return p;
}

I don’t understand what does sortcmp() do? And does skip function return non null terminated part from char *p or what?
Please explain.

Answer 1

This is complete guesswork, since I don’t have a copy of the book, but it looks like these functions are for working with an unconventional string format consisting of a sequence of “words” separated by null characters.

• wordncmp() compares the first k words, where k is presumably a global variable to be set before calling the function.
• sortcmp() takes pointers to string pointers, and is presumably intended as the comparator when sorting an array of string pointers using qsort().
• skip() skips over n words in a string.

In C++, you’d be better off using the standard String and Algorithms libraries to do this sort of thing; there’s rarely a good reason to mess around with pointers and unconventional string representations.