length-of-last-word 最后一个单词的长度

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",
return5.

解法一：

顺序遍历，有单词则len++，有空格且下一位为单词则len=0，直到末尾输出len

class Solution {
public:
    int lengthOfLastWord(const char *s) {
        int len=0;
        while(*s)
        {
            if(*s++!=' ')
                len++;
            else if(*s&&*s!=' ')
                len=0;
        }
        return len;
    }
};

解法二：

class Solution {
public:
    int lengthOfLastWord(const char *s) {
        int count = 0;
        int len = strlen(s);
//反向查找，末尾空格忽略，行中出现空格就终止循环
        for(int i = len-1; i >= 0 ; i--){
            if(s[i] == ' '){
                if(count)
                    break;
            }
            else{
                count++;
            }
        }
        return count;
    }
};