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.

思路：

找出最后一个字母的位置end,最后一个单词的第一个字母位置begin.长度len = end -begin.

注意到几种特殊情况：

1）空字符串，返回0

2）全部都是空格

3）最后几个字符是空格

#include <iostream>using namespace std;int getLethOfLastWord(string s){int len = s.size();if(len == 0) return 0;while(len > 0 && s[len-1] == ' '){len --;}int end = len;while(len > 0 && s[len-1]!= ' '){len--;}int begin = len;int res = end - begin;return res;}void main(){string s=" a bcd  ";int res = getLethOfLastWord(s);printf("The last word length is %d.\n",res);}