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) {
    if (num>=0 and num< 10)
        return num;
    while (num>=10) 
    {
        int sum = 0;
        while (num!=0)
         {sum+=num%10;
          num = num/10;
         }
         num = sum;
    }
    return num;
       
    }
};