Length of Last Word

class Solution {
public:
    int lengthOfLastWord(string s) {
        int length = 0;
        int index = s.find_last_not_of(" ");
        if(index == -1) {
            return length;
        }
        while(index >= 0 && s[index--] != ' ') {
            length++;
        }
        return length;
    }
};