【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.

class Solution {
public:
    int lengthOfLastWord(const char *s) {
        int total_len = strlen(s);
        if (total_len == 0) return 0;
        int ret = 0, i = total_len - 1;
        while (i >= 0 && s[i] == ' ') --i;
        while (i >= 0 && s[i] != ' ') {
            ++ret;
            --i;
        }
        return ret;
    }
};

按题意数就可以了..