From: Stefano Crocco <stefano.crocco@...>
Date: 2008-03-24T23:42:50+09:00
Subject: Re: Beginner's question

On Monday 24 March 2008, 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.

Inside the while loop, you need to do essentially three things:
a) display the verse related to the current number of bottles
b) break a bottle (that is, decrease the variable bottle by one)
c) display the verse related to the new number of bottles

Each of these goals may be translated in a line of code:

while bottles !=0
  puts bottles.to_s + "bottles of beer on the wall, " + bottles.to_s + "bottles of beer."
  bottles -= 1
  puts "Take one down and pass it around, "+ bottles.to_s + "bottles of beer on the wall."
end

This works almost perfectly, except for the fact that it doesn't treat the
case of one bottle and of 0 bottle in a special way (when there's only one 
bottle, it should print 1 bottle, when there are no more bottles, it should 
write so). To correct this, you should insert some if statements inside the 
while loop.

I hope this helps

Stefano