Sum of digits in a number

Question

This function is supposed to return the sum of all the digits in a number.

def sum_digits(num):
    if int(num) <= 0:
        return 0
    else:
        sum = 0
        while int(num) != 0:
            n = int(num) % 10
            num = int(num) / 10
            sum = int(sum + n)
        return sum

It works fine for smaller numbers, but if i enter for example number 999999999999999999999999999999999 it returns 74 instead of 297.

Thanks for help

If you step through your code you should quickly see what it does wrong. — mkrieger1, Nov 09 '20 at 11:52
``/`` is regular division, aka floating point math – use ``//`` for floor division, aka integer math. ``float`` is not sufficient to hold 999999999999999999999999999999999 accurately. — MisterMiyagi, Nov 09 '20 at 11:59

danyroza · Accepted Answer · 2020-11-09T13:56:17.520

You need to divide with (//) instead of (/), because that would return a floating number. You need to do something like this:

def sum_digits(num):
    num = int(num)
    if num <= 0:
        return 0
    else:
        sum = 0
        while num != 0:
            n = num % 10
            num //= 10
            sum +=  n
        return sum

(I reformated your code a little for better readability.)

edit: typo fixed

score -1 · Answer 2 · answered Nov 09 '20 at 12:01

-1

I approached your problem a little different

number = 999999999999999999999999999999999
    number = str(number)
    sum = 0
    for digit in number:
        digit = int(digit)
        sum = digit+sum
    print(sum)

answered Nov 09 '20 at 12:01

Kerem Boyalı

11
3

1

That doesn't explain what is the problem, though. – mkrieger1 Nov 09 '20 at 12:01
Please do not re-use names of builtins such as ``sum`` – especially not if they would concisely solve the problem. – MisterMiyagi Nov 09 '20 at 12:03

Sum of digits in a number

2 Answers2