题目1124：Digital Roots

import java.io.IOException;import java.io.FileReader;import java.io.InputStreamReader;import java.io.BufferedReader;import java.util.Scanner;import java.util.Vector;class Main{public static final boolean DEBUG = false;public static int f(String s){int sum = 0;for (int i = 0; i < s.length(); i++) {sum += s.charAt(i) - '0';}if (sum < 10) return sum;else {String tmp = new Integer(sum).toString();return f(tmp);}}public static void main(String[] args) throws IOException{Scanner cin;String s;if (DEBUG) {cin = new Scanner(new FileReader("d:\\OJ\\uva_in.txt"));} else {cin = new Scanner(new InputStreamReader(System.in));}while (cin.hasNext()) {s = cin.next();if (s.compareTo("0") == 0) break;System.out.println(f(s));}}}