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) {
const char *p=s,*q;
int len=0;
if(p==NULL||*p=='\0'){
return len;
}
while(p&&*p!='\0'){
p++;
}
q=p-1;
while(q!=s&&*q==' '){//去除末尾空格，如 "abc  "->3
q--;
}
while(q!=s&&*q!=' '){
len++;
q--;
}
return *q==' '?len:len+1;//如 " "->0,"a "->1
}
};