Length of Last Word

Given a string s consists of upper/lower-case alphabets and empty space characters' ', return the length of last word in the string.

If the last word does not exist, return 0.

Note: A word is defined as a character sequence consists of non-space characters only.

For example,
Given s = "Hello World",
return 5.

Solution:

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