Course of Raku / Addendum 🆕 / Flow and functions / Control flow and logic / Exercises / Rock, paper, scissors

Solution: Rock, paper, scissors

Here is a possible solution to the task.

Code

my %beats = rock => 'scissors', scissors => 'paper', paper => 'rock';

sub winner($a, $b) {
    return 'tie' if $a eq $b;
    return %beats{$a} eq $b ?? "$a wins" !! "$b wins";
}

for <rock scissors>, <paper rock>, <paper paper> -> ($a, $b) {
    say "$a vs $b: { winner($a, $b) }";
}

🦋 You can find the source code in the file rock-paper-scissors.raku.

Output

rock vs scissors: rock wins
paper vs rock: paper wins
paper vs paper: tie

Comments

1. The %beats hash encodes the rules: each move maps to the move it defeats. That turns judging into a single lookup instead of a long chain of conditions.

2. If %beats{$a} is the opponent’s move, then $a wins; otherwise (equal moves already handled) $b wins.

Course navigation

← Rock, paper, scissors   |   Sum until over a hundred →