Given a non-negative integer num, repeatedly add all its digits until the result has only one digit. For example: Given num = 38, the process is like: 3 + 8 = 11, 1 + 1 = 2. Since 2 has only one digit, return it.
public class Solution { public int addDigits(int num) { String numStr=Integer.toString(num); int total=0; for(int i=0; i<numStr.length(); i++){ total=total+Character.getNumericValue(numStr.charAt(i)); } if(total<10){ return total; } else{ return addDigits(total); } } }
原文：http://www.cnblogs.com/incrediblechangshuo/p/5662217.html