Sum of digits

Problem: Compute the sum of digits for the given number as a single digit number.

Example:

sum_of_digits(5674) = 4 (5+6+7+4=22, 2+2=4)


Solution in Python:

def sum_of_digits(n):

    """
    Author: Mayur P Srivastava
    """

    while n > 9:
        n = sum_of_digits2(n)
    return n


def sum_of_digits2(n):
    sum = 0

    while n > 0:
        sum += n % 10
        n = n // 10

    return sum

Concepts Learned: Loops and numbers.