Course of Raku / Functional, concurrent, reactive, and web programming / Functional programming / Recursion / Exercises
Sum of digits
Problem
Write a recursive subroutine sum-digits that returns the
sum of the decimal digits of a non-negative integer. For a number below
10 the answer is the number itself; otherwise add the last
digit ($n % 10) to the digit sum of the rest
($n div 10).
Print sum-digits(1234).
Example
The program prints:
10