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.

先把字符串最后的空格去掉，然后统计从后往前第一个单词中字母的个数。

int lengthOfLastWord(char *s) {
    if(s == NULL) return 0;
    int i = strlen(s)-1;
    int count = 0;
    while(s[i] == ' ') i--;
    while(s[i] != ' ' && i>=0){
        count++;
        i--;
    }
    return count;
}