Course of Raku / Addendum 🆕 / Flow and functions / Subroutines and functional style / Exercises / Digit sum by recursion

Solution: Digit sum by recursion

Here is a possible solution to the task.

Code

sub digit-sum($n) {
    return $n if $n < 10;
    return $n % 10 + digit-sum($n div 10);
}

say digit-sum(12345);

🦋 You can find the source code in the file recursive-digit-sum.raku.

Output

15

Comments

1. The base case is a single-digit number, which is its own digit sum. Otherwise the routine peels off the last digit with $n % 10 and recurses on the rest, $n div 10.

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