Length of Last Word

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.

class Solution {/*Straightforward, and easy**/
public:
    int lengthOfLastWord(const char *s) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        if (!s) return 0;
        int size = 0;
        while(s[size]){
            ++size;
        }
        int index = size-1;
        size = 0;
        while(index >= 0 && s[index] == ' ') --index;
        while(index >= 0 && s[index] != ' '){--index; ++size;}
        return size;
    }
};