sub dec2bin {
    my $str = unpack("B32", pack("N", shift));
    $str =~ s/^0+(?=\d)//;   # otherwise you'll get leading zeros
    return $str;
}
sub bin2dec {
    return unpack("N", pack("B32", substr("0" x 32 . shift, -32)));
}
[download]

#or, in v5.6.0
sub dec2bin {return sprintf "%b",shift }
#and
sub bin2dec{ return oct"0b$_[0]"}
[download]

#!/user/local/bin/perl print "\nEnter the num:"; @rem=(); $dec =<STDIN>; print "converting to binary"; while ($dec> 0) { @rem$i++ = $dec % 2; $dec= int ($dec/2); } print reverse(@rem);

I have 32 bits, that I need to convert to decimal. This seems to be a problem for bin2doc. Do I encounter an overflow?

Re: How do I convert between decimal and binary?

Originally posted as a Categorized Answer.

chomp (my $inputNumber = <STDIN>);
my @array;

while ($inputNumber>=1) 
{
    my $remainder;
    my $quo;

    if ($inputNumber == 1) 
    {
        unshift @array,$inputNumber;
        last;
    }

    $remainder = $inputNumber % 2;
    print "Remainder = $remainder\n";
    $quo = $inputNumber / 2;
    print "Quo = $quo\n";

    unshift @array,$remainder;
    $inputNumber = $quo;
}
print"\n";
print @array;
print"\n";
[download]

Either I'm missing something... or there's a little something missing here (like assigning a value to @array):

C:\>1071258.pl 3

Argument "" isn't numeric in numeric ge (>=) at 1071258.pl line 8, <ST
+DIN> line 1.
[download]

where line 8 in my code reflects inclusion of hashbang, etc... and contains while ($inputNumber>=1) and is Ln 4 in OP.

---

Update: The node at http://www.perlmonks.com/index.pl?node_id=1071258, the parent of this post, has disappeared (been deleted? by Q&AEditors?) as of approx 0700 Eastern US, 20 Jan 2014, and this reply node contains no link to OP (nor does morgon's similar reply). So, for the record, the OP contained what follows, minus the hashbang, pragmas and source-identifying comment:

#!/usr/local/bin/perl
use 5.016; use warnings; 
# 1071258  (Q&A: convert between decimal and binary)

chomp (my $inputNumber = <STDIN>);
my @array;

while ($inputNumber>=1) 
{
    my $remainder;
    my $quo;

    if ($inputNumber == 1) 
    {
        unshift @array,$inputNumber;
        last;
    }

    $remainder = $inputNumber % 2;
    print "Remainder = $remainder\n";
    $quo = $inputNumber / 2;
    print "Quo = $quo\n";

    unshift @array,$remainder;
    $inputNumber = $quo;
}
print"\n";
print @array;
print"\n";
[download]

Come, let us reason together: Spirit of the Monastery

This should not appear as "categorized answers" as it may mislead others.

Apart from the fact the you don't do any error-handling (e.g. your program does not work for negative numbers, but does not raise an error) the implementation is questionable.

If your printing of intermediate values is not considered an essential feature you could e.g. simply do this:

my $binary = sprintf "%b", $inputNumber;
my @array = split //, $binary;  # if you absolutely want the bits as a
+n array
[download]

which may not even be the optimal solution but is clearer, shorter and faster than your attempt.

Originally posted as a Categorized Answer.

Originally posted as a Categorized Answer.