#!/usr/bin/perl -wuse strict;use v5.10;sub swap { $_[0] = $_[0] + $_[1]; $_[1] = $_[0] - $_[1]; $_[0] = $_[0] - $_[1];}my $a = 0;my $b = 1;while ($b < $ARGV[0]) { $a += $b; say $b; swap($a, $b);}