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.

Analyse: Considering the situation s.t. the last few numbers of the string are all ' ' .

class Solution {
public:
    int lengthOfLastWord(string s) {
        int len = s.length() - 1;
        int result = 0;
        
        while(s[len] == ' ') len--;
        
        for(int i = len; i >= 0; i--){
            if(s[i] != ' ') result++;
            else break;
        }
        return result;
    }
};