#!/usr/bin/perl
use strict;
use warnings;

my @array = (3,-3);

foreach $_ (@array){
    if ($_ < 0) {
	print "Value: $_ is negative\n";
	my $negative_b = dec2bin($_,32,"i");
	print "Negative binary: ".$negative_b."\n";
	my $negative_d = bin2dec($negative_b,"i");
	print "Negative_binary back to decimal: ".$negative_d."\n";
    }
    else {
	print "Value: $_ is possitive\n";
	my $possitive_b = dec2bin($_,8,"N");
	print "Possitive binary: ".$possitive_b."\n";
	my $possitive_d = bin2dec($possitive_b,"N");
	print "Possitive_binary back to decimal: ".$possitive_d."\n";
    }
}

sub dec2bin {
    my $bits      = shift;
    my $possition = shift;
    my $template  = shift;
    my $str = unpack("B32", pack($template, $bits));
    $str = substr $str, -$possition;
    return $str;
}

sub bin2dec {
    my $bits     = shift;
    my $template = shift;
    return unpack($template, pack("B32", substr("0" x 32 . $bits , -32)));
}

__END__

Value: 3 is possitive
Possitive binary: 00000011
Possitive_binary back to decimal: 3
Value: -3 is negative
Negative binary: 11111101111111111111111111111111
Negative_binary back to decimal: -3