58. Length of Last Word

原题：
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.

Example:

Input: "Hello World"
Output: 5

翻译：
给你一个由大小写字母和空格组成的字符串s, 返回字符串最后一个单词的长度

如果最后一个单词不存在就返回0
注意: A单词定义为仅由非空格字符组成字符序列。

例:

Input: "Hello World"
Output: 5

C程序

int lengthOfLastWord(char * s){
    int num = 0;
    int prev = 0;
    while(*s!='\0')
    { 
        if(*s == ' ')
        {
            if(num!=0)prev = num;
            num = 0;
        }
        if(*s<=90 && *s>=65 || *s>=97 && *s<=122)
        {
            ++num;
        }
        ++s;
    }
    if(num==0)return prev;
    return num;
}

总结：
本题难点是对最后为空格的字符串的处理