leetcode 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. 

简单题，不过我刚开始少想了一种情况，就是“hello world      ”后面有很多空格，但是最后一个单词还是world

所以我们要从第一个不是空格的字符开始判断，然后再到下一个空格停止。

class Solution {
public:
    int lengthOfLastWord(string s) {
        if(s=="") return 0;
        int len=s.length();
        int i=len-1;
        int count=0;

        while(s[i]==' ') i--;
        for(;i>=0;i--)
        {
            if(s[i]!=' ') count++;
            else break;
        }
        return count;
    }
};