[LeetCode刷题记录]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：指针扫描一次，遇到空格置零。要特别注意多个空格的情况。要判断空格后面是否为空格，或者是指到字符串尾部。

对char *操作时注意一些细节问题。

class Solution {
public:
    int lengthOfLastWord(const char *s) {
        if(s==NULL)
            return 0;
        int ret=0;
        int flag=0;
        while(*s){
            if(*s!=' ')
                ++ret;
            if(*s==' '&&*(s+1)&&*(s+1)!=' ')
                ret=0;
                ++s;
        }
        return ret;
    }
};