1 files changed, 41 insertions, 0 deletions
diff --git a/perl/p2.pl b/perl/p2.pl
new file mode 100644
index 0000000..ec85ec1
--- /dev/null
+++ b/perl/p2.pl
@@ -0,0 +1,41 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+
+# Functional (naïve)
+sub iter1 {
+	my ($fibs, $acc) = @_;
+	my ($a, $b) = @$fibs;
+	if ($a > 4_000_000) {
+		return $acc;
+	} else {
+		iter1([$b, $a+$b], $a & 1 ? $acc : $acc + $a);
+	}
+}
+print iter1([1, 2], 0);
+print "\n";
+
+# Functional (tail recursive)
+sub iter2 {
+	my ($fibs, $acc) = @_;
+	my ($a, $b) = @$fibs;
+	if ($a > 4_000_000) {
+		return $acc;
+	} else {
+		@_ = ([$b, $a+$b], $a & 1 ? $acc : $acc + $a);
+		goto &iter2;
+	}
+}
+print iter2([1, 2], 0);
+print "\n";
+
+# Imperative
+my ($a, $b) = (1, 2);
+my $resp = 0;
+do {
+	$resp += $a unless ($a & 1);
+	($a, $b) = ($b, $a+$b);
+} while ($a <= 4_000_000);
+
+print "$resp\n"