计算最后一个单词长度

import java.util.Scanner;

public class Hello {
    public static void main(String args[])
    {
        Scanner stdin = new Scanner(System.in);
        String str = stdin.nextLine();
        str = str.trim();
        int len = str.length();
        int index = 0;
        while ( len > 0 )
        {
            while ((len-1 >= 0) && (str.charAt(len-1) != ' '))
            {
                --len ;
                 ++index;
            }
            System.out.println("last word len = " + index);

            str = stdin.nextLine();
            len = str.length();
            System.out.println(str);
            System.out.println(len);
        }
    }
}