Add Digits

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 result = 0;
            while(num != 0){
                result += num%10;
                num = num/10;
            }
            num = result;
        }
        return num;
    }
};