Course of Raku / Functional, concurrent, reactive, and web programming / Functional programming / Recursion / Exercises / Count up

Solution: Count up

Here is a possible solution to the task.

Code

sub countup($n) {
    return if $n < 1;
    countup($n - 1);
    say $n;
}

countup(3);

🦋 You can find the source code in the file countdown.raku.

Output

1
2
3

Comments

The base case return if $n < 1 still stops the recursion once the count passes zero.
The order of the last two lines is what makes it count up: each call first recurses all the way down to the base case, and only then prints its own number as the calls unwind. So 1 is printed first and $n last.

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