[LeetCode]Length of Last Word

题目描述：(链接)

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.

解题思路：

简单题，注意去掉字符串尾部的空格！！

class Solution {
public:
    int lengthOfLastWord(string s) {
        int len = s.size();
        int j = len - 1;
        while (s[j] == ' ') { --j; }
        
        int index = 0;
        for (int k = 0; k < j; ++k) {
            if (s[k] == ' ') {
                index = k + 1;
            }
        }
        
        return j - index + 1;
    }
};