From: Vincent Fourmond <vincent.fourmond@9online.fr>
Date: 2006-12-24T10:50:29+09:00
Subject: Re: Beginner issues

Anime Junkie wrote:
> Hello all,
> 
> I'm not much of a developer but will be supporting RoR in the near
> future and thought I would familiarize myself with Ruby a bit.  I'm
> using the "Programming Ruby" book and find that a lot of the examples
> don't work.  They use too much pseudo code in my opinion.  Anyhow, could
> anyone explain why the following doesn't work?  I've put comments in
> where I thought necessary.
> 
> class Song
> 
> attr_reader :duration
> 
> def initialize(duration)
>   @duration = duration
> end
> 
> def duration_in_mins=(new_duration)
>   @duration = (new_duration*60).to_i
> end
> 
> end # End Song
> 
> song = Song.new(360)
> 
> puts song.duration # this prints 360
> 
> song.duration_in_mins = 2
> 
> puts song.duration  # this prints out 120
> 
> puts song.duration_in_mins  # I assumed that this would print 2 but
> produces the error "undefined method `duration_in_mins'"

  In the code, you define the method duration_in_mins=, which handles
the assignment of @duration. However, you don't define a method
duration_in_mins to return its value in minutes. Adding

def duration_in_mins
  @duration/60.0
end

should do it.

  Cheers,

	Vince

-- 
Vincent Fourmond, PhD student
http://vincent.fourmond.neuf.fr/