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

.

int lengthOfLastWord(const char *s) {
int index=strlen(s)-1;
int len=0;
while(index>-1&&*(s+index)==' ')
index--;
if(index<0)
return 0;
while(*(s+index)!=' '&&index>=0){
index--;
len++;
}
return len;
}