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#!/usr/bin/perl
use warnings;
use strict;
use feature 'say';
# Problem: https://perlweeklychallenge.org/blog/perl-weekly-challenge-119/ TASK #1
my $d = shift || 0;
my $f = BinaryFOO->new();
say $f->nibble_swap($d);
exit;
package BinaryFOO;
sub new {
return bless {}, shift;
}
sub dec_to_bin {
my $self = shift;
my $dec = shift;
return sprintf "%b", $dec;
}
sub bin_to_dec {
my $self = shift;
my $bin = shift;
return oct("0b".$bin);
}
sub is_palidrome {
my $self = shift;
my $bin = shift;
return ($bin eq reverse($bin));
}
sub nibble_split {
my $self = shift;
my $bin = shift;
# make sure we have an octet (8 char length minimum)
$bin = '0'x8 . $bin;
$bin = substr($bin,-8);
# split into 2 nibbles
return (substr($bin,0,4), substr($bin,-4));
}
sub nibble_swap {
my $self = shift;
my $dec = shift;
return "$dec is greater than 255" if ($dec > 255);
my @n = $self->nibble_split($self->dec_to_bin($dec));
return $self->bin_to_dec($n[1].$n[0]);
}
1;
__END__
./ch-1.pl
0
./ch-1.pl 101
86
./ch-1.pl 18
33
./ch-1.pl 255
255
./ch-1.pl 15 # 00001111 => 11110000
240
./ch-1.pl 240
15
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