Consider a recursive function sumDigitsR $($

$um)$ that returns the sum of the digits of the input parameter, which is an integer called num. It can be assumed that 'num' is a non$-$negative

For example: sumDigitsR $(1983)=21.$

If sumDigitsR was re$-$written into an iterative version, what would be the space complexity of the iterative algorithm?

$O(n)$

O$(($:$n^2$