Re: converting binary to decimal

Have you considered grouping digits like the big* routines? This runs in under 70 milliseconds.

#!/usr/bin/perl

use strict; # https://perlmonks.org/?node_id=11165274
use warnings;

my $size = 18; # NOTE may depend on word size
my $n = 10 ** $size; # NOTE size needed for zero padding in sprintf
my @number = 0;

my $binary = 1 . 0 x 8192;

for ( split //, $binary )
  {
  my $carry = $_;
  for ( @number )
    {
    $_ += $_ + $carry;
    $carry = int $_ / $n;
    $_ %= $n;
    }
  $carry and push @number, $carry;
  }
my $decimal = (join '', map sprintf('%0*d', $size, $_), reverse @numbe
+r)
  =~ s/0+(?=.)//r;
#use Data::Dump 'dd'; dd $binary;
print "$decimal\n";
[download]

Outputs:

1090748135619415929462984244733782862448264161996232692431832786189721
+331849119295216264234525201987223957291796157025273109870820177184063
+610979765077554799078906298842192989538609825228048205159696851613591
+638196771886542609324560121290553901886301017900252535799917200010079
+600026535836800905297805880952350501630195475653911005312364560014847
+426035293551245843928918752768696279344088055617515694349945406677825
+140814900616105920256438504578013326493565836047242407382442812245131
+517757519164899226365743722432277368075027627883045206501792761700945
+699168497257879683851737049996900961120515655050115561271491492515342
+105748966629547032786321505730828430221664970324396138635251626409516
+168005427623435996308921691446181187406395310665404885739434832877428
+167407495370993511868756359970390117021823616749458620969857006263612
+082706715408157066575137281027022310927564910276759160520878304632411
+049364568754920967322982459184763427383790272448438018526977764941072
+715611580434690827459339991961414242741410599117426060556483763756314
+527611362658628383368621157993638020878537675545336789915694234433955
+666315070087213535470255670312004130725495834508357439653828936077080
+978550578912967907352780054935621561090795845172954115972927479877527
+738560008204118558930004777748727761853813510493840581861598652211605
+960308356405941821189714037868726219481498727603653616298856174822413
+033485438785324024751419417183012281078209729303537372804574372095228
+703622776363945290869806258422355148507571039619387449629866808188769
+662815778153079393179093143648340761738581819563002994422790754955061
+288818308430079648693232179158765918035565216157115402992120276155607
+873107937477466841528362987708699450152031231862594203085693838944657
+061346236704234026821102958954951197087076546186622796294536451620756
+509351018906023773821539532776208676978589731966330308893304665169436
+185078350641568336944530051437491311298834367265238595404904273455928
+723949525227184617404367854754610474377019768025576605881038077270707
+717942221977090385438585844095492116099852538903974655703943973086090
+930596963360767529964938414598185705963754561497355827813623833288906
+309004288017321424808663962671333528009232758350873059614118723781422
+101460198615747386855096896089189180441339558524822867541113212638793
+675567650340362970031930023397828465318547238244232028015189689660418
+822976000815437610652254270163595650875433851147123214227266605403581
+781469090806576468950587661997186505665475715792896
[download]

Comment on Re: converting binary to decimal Select or Download Code

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Re^2: converting binary to decimal by harangzsolt33 (Deacon) on Jun 26, 2025 at 17:33 UTC
Perl says, "Bareword found where operator expected," and it's pointing to the regex on this line: my $decimal = (join '', map sprintf('%0*d', $size, $_), reverse @number) =~ s/0+(?=.)//r; I don't know why I'm getting this error, and don't know how to fix it, because honestly, I don't even understand what this line does. I tried to remove this line entirely from the code and just "print join('-', @number);" but all I see is a list of very big numbers... and I don't even understand how the algorithm is supposed to work. In other words, I am completely lost at this one.	[reply]
Re^3: converting binary to decimal by ysth (Canon) on Jun 26, 2025 at 19:23 UTC
You seem to be running an extremely old version of perl. Try changing it it: `(my $decimal = join '', map sprintf('%0*d', $size, $_), reverse @numbe +r) =~ s/0+(?=.)//;` [download]	[reply] [d/l]
Re^3: converting binary to decimal by hippo (Archbishop) on Jun 26, 2025 at 17:59 UTC
Perl says, "Bareword found where operator expected," Use a version of Perl released in the last 15 years and this problem does not occur. 🦛	[reply]
Re^4: converting binary to decimal by harangzsolt33 (Deacon) on Jun 27, 2025 at 03:15 UTC
Okay. I do use a modern Perl when I am on Linux. But when I am on Windows, I like to use TinyPerl.	[reply]
Re^3: converting binary to decimal by tybalt89 (Monsignor) on Jun 26, 2025 at 19:41 UTC
replace `my $decimal = (join '', map sprintf('%0d', $size, $_), reverse @numbe +r) =~ s/0+(?=.)//r;` [download] with `s/0+(?=.)// for my $decimal = join '', map sprintf('%0d', $size, $_), + reverse @number;` [download] It's just doing math in base `$n` which is 10**18 in this case (because that's the largest power of 10 that works on my machine). Change `$size` to 1 to see it work (more slowly) in base 10. It's doing the same kind of thing that 'bigint' does...	[reply] [d/l] [select]
Re^4: converting binary to decimal by harangzsolt33 (Deacon) on Jun 27, 2025 at 03:13 UTC
The output I'm getting looks like this. And I don't know why. I tried both suggestions, and it's the same with both: 000000001-00000000000000001-00000000000000001-00000000000000001-000000 +0000000000 1-00000000000000001-00000000000000001-00000000000000001-00000000000000 +001-000000 00000000001-00000000000000001-00000000000000001-00000000000000001-0000 +0000000000 001-00000000000000001-00000000000000001-00000000000000001-000000000000 +00001-0000 0000000000001-00000000000000001-00000000000000001-00000000000000001-00 +0000000000 00001-00000000000000001-00000000000000001-00000000000000001-0000000000 +0000001-00 000000000000001-00000000000000001-00000000000000001-00000000000000001- +0000000000 0000001-00000000000000001-00000000000000001-00000000000000001-00000000 +000000001- 00000000000000001-00000000000000001-00000000000000001-0000000000000000 +1-00000000 000000001-00000000000000001-00000000000000001-00000000000000001-000000 +0000000000 1-00000000000000001-00000000000000001-00000000000000001-00000000000000 +001-000000 00000000001-00000000000000001-00000000000000001-00000000000000001-0000 +0000000000 001-00000000000000001-00000000000000001-00000000000000001-000000000000 +00001-0000 0000000000001-00000000000000001-00000000000000001-00000000000000001-00 +0000000000 00001-00000000000000001-00000000000000001-00000000000000001-0000000000 +0000001-00 000000000000001-00000000000000001-00000000000000001-00000000000000001- +0000000000 0000001-00000000000000001-00000000000000001-00000000000000001-00000000 +000000001- 00000000000000001-00000000000000001-00000000000000001-0000000000000000 +1-00000000 000000001-00000000000000001-00000000000000001-00000000000000001-000000 +0000000000 1-00000000000000001-00000000000000001-00000000000000001-00000000000000 +001-000000 00000000001-00000000000000001-00000000000000001-00000000000000001-0000 +0000000000 001-00000000000000001-00000000000000001-00000000000000001-000000000000 +00001-0000 0000000000001-00000000000000001-00000000000000001-00000000000000001 [download]	[reply] [d/l]
Re^5: converting binary to decimal by tybalt89 (Monsignor) on Jun 27, 2025 at 04:08 UTC
Re^6: converting binary to decimal by harangzsolt33 (Deacon) on Jul 02, 2025 at 15:51 UTC
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