leetcode Add Digits

题目连接

https://leetcode.com/problems/add-digits/  

Add Digits

Description

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.

class Solution {
public:
	int addDigits(int num) {
		while (num >= 10) {
			int ret = 0;
			do ret += num % 10; while (num /= 10);
			num = ret;
		}
		return num;
	}
};