comparing version numbers in c

Question

I am seeing a lot of answers for this problem in other languages but I am trying to find out a way to compare 2 version numbers given as strings. For example

Answer 1

A minimalist C version that only tokenizes the first non-matching component. Uses strchr() and strtoul().

int version_compare(char *s1, char *s2)
{
    char *delim = ".:-";
    while(1) {
        if (*s1 == *s2)  {
            if (!*s1)
                return 0;
            s1++; s2++;
        } else if (strchr(delim, *s1) || !*s1) {
            return -1;
        } else if (strchr(delim, *s2) || !*s2) {
            return 1;
        } else {
            int diff;
            char *end1, *end2;
            diff = strtoul(c1, &end1, 10) - strtoul(c2, &end2, 10);
            if (!diff) {
                c1 += (end1 - c1);
                c2 += (end2 - c2);
            } else {
                return diff;
            }
        }
    }
}