http://www.perlmonks.org?node_id=191643
Category: Fun Stuff
Author/Contact Info Kevin Cohe
Description: This was my first program. I did it after about an hour or two of reading Learning Perl. I relize there are other programs that do the same thing more efficiently, but this is my first program and I have much to learn.
#!/usr/bin/perl -w

print "Welcome to 99 bottles of beer on the wall\n";

print "How many bottles of beer do you want on the wall\n";

$beer=<STDIN>;

do{

$beer1=$beer-1;

if($beer1>=0){

print "$beer bottles of beer on the wall, $beer bottles of

 beer. Take one down pass it around $beer1 bottles of beer 

on the wall\n";

$beer=$beer-1;

}

}while($beer>0);
Replies are listed 'Best First'.
(jeffa) Re: 99 bottles of beer on the Wall
by jeffa (Bishop) on Aug 21, 2002 at 04:35 UTC
    Not bad for a first program ... here is a less redundant version in the interest of helping you learn more:
    #!/usr/bin/perl -w use strict; my $beer = abs shift || 99; print how_many($beer), ",\n", how_many($beer), ".\n", "Take one down, pass it around,\n", how_many(--$beer), ".\n\n" while $beer; sub how_many { my $numb = shift; return $numb . ' bottle' . ($numb == 1 ? '' : 's') . ' of beer on the wall' ; }
    Instead of asking the user for the number of beers *hic*, the code instead gets the number as a command line argument. If no argument is supplied, it instead uses a default value of 99. Also, it counts down until $beer is a false value instead of until $beer is 0 - hence, we have to take the absolute value of that command line argument lest the user give us a negative value and spin us off into an infinite loop. This version also uses a subroutine and a ternary operator (expr ? true : false), which is just a fancy if-else that is used to avoid spouting out '1 bottles'.

    Keep on coding! :)

    UPDATE: oops, you are correct mystik - and yes, my vision was blurry last night! :D (typo corrected)

    jeffa

    L-LL-L--L-LL-L--L-LL-L--
    -R--R-RR-R--R-RR-R--R-RR
    B--B--B--B--B--B--B--B--
    H---H---H---H---H---H---
    (the triplet paradiddle with high-hat)
    

      I'm pretty sure that you need to change how_many($beer--) to how_many(--$beer). After you take one down, and pass it around, unless your vision is blurrey, there's one fewer beer.

      For the benefit of those that don't know, $var-- returns the value of $var, then decrements it. --$var first decrements, then returns $var

      If the eval engine in my brain is correct, --$var++ will return $var - 1, but the value of $var will still be the same ;)

      Getting rid of the warning and making it just a little bit prettier:
      #!/usr/bin/perl -w use strict; use Lingua::EN::Nums2Words; my $beer = shift || 99; $beer = abs($beer); print how_many($beer), ",\n", how_many($beer), ".\n", "Take one down, pass it around,\n", how_many(--$beer), ".\n\n" while $beer; sub how_many { my $numb = &num2word(shift); $numb =~ s/(\w)(.*)/\u$1\L$2/; return $numb . ' bottle' . ($numb eq 'One' ? '' : 's') . ' of beer on the wall' ; }
      Requires Lingua::EN::Nums2Words.
      ()-()
       \"/
        `                                                     
      
        Here's the first joke that I can remember telling as a kid. It still cracks em up today.
        #!/usr/bin/perl -w use strict; use Lingua::EN::Nums2Words; my $beer = shift || 99; $beer = abs($beer); for (-9..$beer) { print how_many($beer), ",\n", how_many($beer), ".\n", "Take one down, pass it around,\n", how_many(--$beer), ".\n\n" } sub how_many { my $numb = &num2word(shift); $numb =~ s/(\w)(.*)/\u$1\L$2/; return $numb . ' bottle' . ($numb eq 'One' ? '' : 's') . ' of beer on the wall' ; }
        ()-()
         \"/
          `                                                     
        
      And here's a different way:
      #!/usr/bin/perl use strict; use warnings 'all'; use Lingua::EN::Inflect; my $beer = abs (shift || 99); sub UNIVERSAL::TIEHASH {bless [] => shift} sub UNIVERSAL::FETCH {no strict 'refs'; &{"Lingua::EN::Inflect::" . ref $_ [0]} (split /$;/ => $_ [ +1])} tie my %N => 'NUMWORDS'; tie my %B => 'PL'; print <<"--" while $beer; \u$N{$beer} $B{bottle => $beer} of beer on the wall, $N{$beer} $B{bottle => $beer --} of beer. Take one down, pass it around. \u$N{$beer} $B{bottle => $beer} of beer on the wall. -- package NUMWORDS; package PL; __END__