CS61A SU20 Quiz 1.4 Solution

quizsol1.4.py

import doctest

# To run this solution, run the following command:
# python3 quizsol1.4.py -v

def reverse_digits(n):
    """Given a positive integer n, reverse its digits.
    Do not use strings.
    
    >>> d1 = 12345
    >>> reverse_digits(d1)
    54321
    >>> d2 = 101
    >>> reverse_digits(d2)
    101
    >>> d3 = 100
    >>> reverse_digits(d3)
    1
    """
    result = 0
    while n > 0:
        result = 10 * result + n % 10
        n //= 10
    return result
 
doctest.testmod()