Hello Monks,

Update: Title update from (How to convert an integer 8bit long to binary and vice versa) to (pack and unpack with 8 bit integers).

Lately I have been asking way too many questions, apologies for that. Although that I thought that I was starting to get the conversion process of decimal to binary and binary to decimal, I got stack again.

I want to convert an integer 8 bit long with template format "i" to binary and then convert it pack to decimal with the same format "i". I want to complete the process using pack and unpack.

I have been experimenting with a sample of code. I can not figure it out why is not working properly.

Sample of code:

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

sub dec2bin {
    my $bits      = shift;
    my $size      = shift;
    my $template  = shift;
    my $str = unpack("B$size", pack($template, $bits));
    return $str;
}

sub bin2dec {
    my $bits     = shift;
    my $size     = shift;
    my $template = shift;
    my $substr = substr("0" x $size . $bits , -$size);
    print "Substring: ".$substr."\n";
    my $pack = pack("B$size", $substr);
    print "Pack: ".$pack."\n";
    my $unpack = unpack($template, $pack);
    return $unpack;
}

my $int2bin = dec2bin( 3 , 8 , "i" );

print "Int2bin: ".$int2bin."\n";

my $binary2int = bin2dec( $int2bin , 8 , "i" );

print "Decimal from binary: ".$binary2int."\n";

__END__

Int2bin: 00000011
Substring: 00000011
Pack: 
Use of uninitialized value $binary2int in concatenation (.) or string 
+at test.pl line 32.
Decimal from binary:
[download]

I have broken down the process into pieces in order to detect the error. It seems the error comes from the pack process.

So at this point I can not understand why. I have found a way to by avoid the error by modifying the $template on the sub bin2dec process from "i" (intiger) to "c" (8 bit character). By doing so I get the correct output, but since I am defining B8 I should not have a problem with the unpack process.

So can someone help me understand where I am going wrong, and how to fix my problem?

Thanks in advance for everyone's time and effort to assist me.