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:

Really simple. Following code passes LeetCode Online Large Judge.

class Solution {
public:
    int lengthOfLastWord(const char *s) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        int len = 0, prev = 0;
        for (int i = 0; s[i] != '\0'; i++) {
            if (s[i] != ' ') {
                len++; 
                prev = len;
            }
            else len = 0;
        }
        return len == 0 ? prev : len;
    }
};