165. Compare Version Numbers

int compareVersion(char* version1, char* version2) {  
    int lenversion1 = strlen(version1);  
    int lenversion2 = strlen(version2);  
    int i = 0;  
    int j = 0;  
    int num1 = 0;  
    int num2 = 0;  
  
    while (i < lenversion1 || j < lenversion2)  
    {  
        while (i < lenversion1&&version1[i] != '.')  
        {  
            num1 = 10 * num1 + version1[i]-'0';  
            i++;  
        }  
  
        while (j < lenversion2 && version2[j] != '.')  
        {  
            num2 = 10 * num2 + version2[j]-'0';  
            j++;  
        }  
//先比较小数点之前的数字
  
        if (num1>num2)return 1;  
        else if (num1 < num2)return -1;  

//如果小数点前面数字相等 就比较小数点后面的数字
        i++;  
        j++;  
        num1 = 0;  
        num2 = 0;  
    }  
    return 0;  
}