in reply to (Golf) Kaprekar's Process

Aarrrgghhhh!!! I'm going crazy here. I can't seem to figure out why something is working the way it is; could any of you help me? I left all my debugging print statements there so that you can run it yourself and see the same results. 

sub b { 
  print 'args=',join(",",@_),"\n"; 
  $,=pop()-pop(); 
  print ", = $,\n"; 
  $x=join'',sort split//,$,; 
  print "x = '$x'\n"; 

  ## the line below doesn't seem to work!!
  @_=map{scalar reverse($_),$_ } $x; 
  
  print "\@_ = ",join(",",@_),"\n"; 
  print "\n"; 
  $,==495?0:1+b(@_); 
} 
 
sub c { 
  @a=map{ scalar reverse($_),$_ } pop; 
  print join(",",@a),"\n"; 
} 

c(312);
b(312);

====
Results when run<
====
213,312              ## this is c()
args=312             ## this is b()
, = 312
x = '123'
@_ = 312321,123312

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For some reason, the map statement in b() is resulting in that strange "312321,123312" results ... which for the life of me, I can't figure out why.

I have a feeling it's something stupid, but I can't see it. Can anyone else?

Update: God, I love this place. You write a technical, perl question, one that contains a user-error (such as I did, using $, as a temporary variable (golf, you know)), and you get down voted as much as upvoted. This node of mine has bounced from -1 to 1 so many times my head is spinning. So at what point is a question stupid enough that you shouldn't ask? I seem to remember quite a few people having on their tag lines, and on their tongues, the phrase of "Ask a silly question, be a fool for a minute, don't ask a silly question and be a fool forever.". I guess that doesn't always apply, huh?</rant>

mr.nick ...

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Re: Re: (Golf) Kaprekar's Process
by sean (Beadle) on Jun 17, 2001 at 09:22 UTC
    Your map statement is working fine. The problem is that you have assigned a value to "$,", which is the output field separator variable. Its value is printed when you use a comma in a print statement. 
    $,="bar";
print "foo","baz";

    [download]
    will output:
    foobarbaz
    --sean
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Re: Re: (Golf) Kaprekar's Process
by dimmesdale (Friar) on Jun 17, 2001 at 06:05 UTC
    That's odd...I tried running this on my system. First I just did the map statement, and assigned 123 to x. This worked perfectly. So, I got a little confused as to why it worked for me, and not for you, so I tried to run the whole script. However--and this is quite a big however--it resulted in an infinite loop, printing out large, negative numbers on my machine. Is this the exact code?
[reply]
      Oh, it loops indefinately, all right. I ran it | head. And yes, that is the exact code.

      If you grab the top of the output, do the see the odd value of @_ = 312321,123312? I would think that @_ would contain the same value as the output from c() since it uses the same map statement (- the pop). But I can't shake the feeling I'm missing something simple here (as I often do) :)

      Btw, I split the subroutine up into individual statements for debugging. It used many fewer temporary variables at first.

      mr.nick ...

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