258. 各位相加

//很简单
class Solution 
{
public:
    int addDigits(int num) 
    {
        while(num > 9)
        {
            int temp = 0;
            while(num)
            {
                temp += num % 10;
                num = num / 10;
            }
            num = temp;
        }
        return num;
    }
};