• Mark your post as having spoiler content when you paste code.

    A digital root is the recursive sum of all the digits in a number. Given n, take the sum of the digits of n. If that value has two digits, continue reducing in this way until a single-digit number is produced.

  • Have you read the descriptions?

  • This comment is hidden because it contains spoiler information about the solution

  • Your code's problem is not a kata issue, it's a question.

    It's known that if you get a StackOverflowException while doing tests it'll be incorrectly reported as a NPE. So you should check your code ;-)

  • For some reason, it's giving me a SetUp : System.NullReferenceException : Object reference not set to an instance of an object on my SampleTest? even though the Sample Test on SetUp is num = new Number(); ..