题目：

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. （Easy）

分析：

注意把最后的空格处理掉即可。

代码：

1 class Solution { 2 public: 3     int lengthOfLastWord(string s) { 4         int start = s.size() - 1; 5         int result = 0; 6         while (s[start] == ' ') { 7             start--; 8         } 9         for (int i = start; i >= 0; --i) {10             if (s[i] != ' ') {11                 result++;12             }13             else {14                 return result;15             }16         }17         return result;18     }19 };