From: Jeff Wood <jeff.darklight@...>
Date: 2005-08-22T14:22:17+09:00
Subject: Re: Ruby beginner question 2

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Alucard wrote:

>Hi all!
>
>I'm using ruby 1.82.  This is the code copy from www.ruby-lang.org,
>programming ruby.
>
>And I found that both the following code cannot run, with the following
>error occur:
>
>song_2.rbw:4:in `initialize': wrong number of arguments (3 for 0)
>(ArgumentError)
>	from song_2.rbw:4:in `new'
>	from song_2.rbw:4
>
>So, what is going wrong?
>
>Thanks in advance!
>
>CODE:
>class Song
>  def name
>    @name
>  end
>  def artist
>    @artist
>  end
>  def duration
>    @duration
>  end
>end
>aSong = Song.new("Bicylops", "Fleck", 260)
>aSong.artist
>aSong.name
>aSong.duration
>
>#--------------------------------------------------------------------------------------------
>
>class Song
>  attr_reader :name, :artist, :duration
>end
>aSong = Song.new("Bicylops", "Fleck", 260)
>aSong.artist 	
>aSong.name 	
>aSong.duration
>
>
>
>  
>
Your objects have no constructor method ... therefore, it's simply
relying on the constructor from Object ( which is implicitly inherited ).

So, simply add

def initialize( name, artist, duration )
@name = name
@artist = artist
@duration = duration
end

within either of your class definition examples... then they'll work.

The inherited constructor from Object takes no parameters, and that's
why you are getting the "initialize wrong number of arguments 3 for
0"... You're passing 3 to a no argument constructor...

Hope that helps.

j.


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