From: Jeff Patterson <jeff_patterson@...>
Date: 2008-03-24T23:34:48+09:00
Subject: Re: Beginner's question

Peter Johnsson wrote:
> This question may be a bit too "simple" for this forum which seems to
> target intermediate and advanced users, but if that's the case someone
> could perhaps direct me to a place which is better for asking this
> question?
> 
>  I have just recently decided to try and learn programming (namely
> Ruby), and in order to do so I've been using a tutorial called "learn to
> program" (http://pine.fm/LearnToProgram/).
>  Everything has gone just fine until I reached the 6:th chapter (Flow
> Control) in which the author teaches about among other things branching
> and loop-methods.
> I think I understand most of it, however, I'm having very large
> difficulties with the " A Few Things to Try" part of the chapter.
>  I find the "99 beer bottles"-program utterly impossible to do. I
> realise that I should somehow use the methods listed on the page, but I
> just can seem to know how. My initial idea is to create a variable
> called "bottles" which at first is 99 and then subtract 1 in every new
> verse until the variable hits 0, where I was thinking I could use the
> "while"-method to end the program. Each new value would be inserted into
> the lyrics. It would look something like this I suppose (please don't
> laugh, I know it doesn't really do anything at all).
> 
> bottles = 99
> 
> while bottles != 0
> # Need help here.
> end
> 
> I stumbled upon a site which showed how one scould program this in Ruby
> (http://99-bottles-of-beer.net/language-ruby-1272.html), but the problem
> is it doesn't use the same methods. It's more advanced since it creates
> classes and defines methods, something which I think lies a bit too far
> ahead for me, and I somehow want to learn things in "the right order".
> 
> I'm thankful for any tips as well as code-examples. Thank you very much.

When doing a loop of this type, concentrate on what is static and what 
needs to change at each iteration. In each verse the only thing that 
changes are the numbers so:

while bottles > 0
  after_this_loop = bottles-1
  puts "#{bottles} of beer on the wall. #{bottles} of beer. Take one 
down and pass it around #{bottles=bottles-1} bottles of beer on the 
wall"
  bottles = bottles -1
end

A ruby programmer would probably do something like:

99.downto(1) do |bottles|
 puts "#{bottles} of beer on the wall. #{bottles} of beer. Take one down 
and pass it around #{bottles=bottles-1} bottles of beer on the wall"
end

Now, figure out how to make the verse come out right when bottles = 1
-- 
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