DAY 42 OF 90 · Know when to stop

Add the digits

Easy90 Days of Looping

Inputs

n is a whole number from 0 to 1,000,000.

Your tasks

Create a number total that starts at 0 and a copy rest of n.
Use a while loop that runs while rest is more than 0. Each round, add the last digit of rest (the remainder when dividing by 10) to total, then drop that digit.
Complete digitSum so it returns total. Return it, do not print it.

Example

With n = 4821, digitSum returns 15.

Rules

Do not turn the number into text.

Test data

TEST DATA 1: n is 4821

TEST DATA 2: n is 0

Practice focus

While loops and early exits, for when you don't know how many rounds you need. Binary search, the Euclidean algorithm and graph search are all while loops with a clear stopping rule.

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