use strict;

my $debug = 1;
my $dec= 254;
print "$dec\n";
print shift_left($dec) ;

sub dec2bin {
    my $str = unpack("B32", pack("N", shift));
    $str =~ s/^0+(?=\d)//;   # otherwise you'll get leading zeros
    print "$str\n" if $debug;
    return $str;
}

sub bin2dec {
    return unpack("N", pack("B32", substr("0" x 32 . shift, -32)));
}

sub shift_left {
    my $bin_reversed = reverse dec2bin(shift);
    chop $bin_reversed;
    print ' ' . reverse ($bin_reversed) . '0' . "\n" if $debug;
    return bin2dec(reverse ($bin_reversed) . '0');
}



##</code><code>##

254
11111110
 11111100
252