factorial
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use v5.18;
# http://math-prosto.ru/?page=pages/factorial/factorial.php
sub fac {
my ($n) = @_;
return 1 if $n == 0 || $n == 1;
my $res = 1;
for (my $i = 1; $i <= $n; $i++) {
$res *= $i;
}
return $res;
}
say fac 0;
say fac 1;
say fac 5;
Perl
INFO