LeetCode 165. Compare Version Numbers

Compare two version numbers version1 and version2.
If version1 > version2 return 1, if version1 < version2 return -1, otherwise return 0.

You may assume that the version strings are non-empty and contain only digits and the . character.
The . character does not represent a decimal point and is used to separate number sequences.
For instance, 2.5 is not "two and a half" or "half way to version three", it is the fifth second-level revision of the second first-level revision.

Here is an example of version numbers ordering:

0.1 < 1.1 < 1.2 < 13.37

I was trying to find any c++ split function.....seems like the function strtok can do the job but it is in c. But actually two pointers will work.

    int compareVersion(string version1, string version2) {
        int n1 = 0, n2 = 0;
        int i = 0, j = 0;
        while(i < version1.size() || j < version2.size()) {
            while(i < version1.size() && version1[i] != '.') {
                n1 = n1*10 + (version1[i++] - '0');
            }
            i++;
            while(j < version2.size() && version2[j] != '.') {
                n2 = n2 * 10 + (version2[j++] - '0');
            }
            j++;
            
            if(n1 < n2) return -1;
            else if(n1 > n2) return 1;
            else {n1 = 0; n2= 0;}
        }
        return 0;
    }