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.
在向前遍历的过程中，每次检查当前字符和前一个字符，如果s[i] != '  ', s[i-1] != '  ', 则len++；
如果s[i] != '  ', s[i-1] == '  ', 说明进入了新的单词，len重新置为1.
注意的是如果s以空格为开头，len=0； 否则len=1；
int lengthOfLastWord(const char *s)
{
if( s[0] == '\0')
return 0;

int len,i=0;
if(s[0]==' ')
len=0;
else
len=1;

while( s[++i] != '\0' )
{
if( s[i] != ' ')
{
if( s[i-1] != ' ')
{
len++;
}
else
{
len = 1;
}
}
}

return len;

}