use strict;
use warnings;
use Data::Dumper;

my (@unsorted) = qw(7 3 2 9 5 18 1 4);

my @sorted1 = sort {$a <=> $b} @unsorted;
my @sorted2 = sort {$b <=> $a} @unsorted;

print Dumper @sorted1;
print "---------\n";
print Dumper @sorted2;