[leetcode] Compare Version Numbers

细节题，代码如下：

int compareVersion(string version1, string version2) {        int index1 = 0, index2 = 0;        while(index1 < version1.length() || index2 < version2.length()){            int temp1, temp2;            int end1 = version1.find('.', index1);            int end2 = version2.find('.', index2);            if(index1 == string::npos)                temp1 = 0;            else if(end1 != string::npos)                temp1 = atoi(version1.substr(index1, end1 - index1 + 1).c_str());            else                temp1 = atoi(version1.substr(index1).c_str());            if(index2 == string::npos)                temp2 = 0;            else if(end2 != string::npos)                temp2 = atoi(version2.substr(index2, end2 - index2 + 1).c_str());            else                temp2 = atoi(version2.substr(index2).c_str());            if(temp1 == temp2){                    index1 = end1 == string::npos ? end1 : end1 + 1;                    index2 = end2 == string::npos ? end2 : end2 + 1;            }            else                return temp1 > temp2 ? 1:-1;        }        return 0;    }