leetcode 题解: Length of Last Word

leetcode：

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.

说明：给定一个字符串，返回最后一个word的长度

1）字符串后面可以有空格，所以要去尾部空格

2）可能不含word,所以要判断字符串是否为空、或者是否只含有空格

 class Solution {
 public:
     int lengthOfLastWord(const char *s) {
         int len=strlen(s);
         while(s[len-]==' ') len--; //去尾部空格
         if(len<) return ; //去空格后是否为空字符串
         int i=;
         for(;s[len-]&&s[len-]!=' ';i++,len--); //求最后word长度
         return i;
     }
 };