From: Robert Klemme <bob.news@...>
Date: 2003-12-01T17:12:11+09:00
Subject: Re: New to ruby--trouble with initializing arrays


"Van Jacques" <vanjac12@yahoo.com> schrieb im Newsbeitrag
news:70ae81fd.0311281947.909cec1@posting.google.com...
> I am writing a practice program; the Game of Life. Naturally I am having
troubles.
>
> This will probably be elementary those with experience in programming
with ruby,
> so please tell me the right place to post such questions if this is not
the place.
>
> The program is not running as I think it should.
>
> I think it may be due to the way I set up the arrays, so that many
elements refer to
> the same element, and then later in the program when they should be
different
> they remain the same.

Does this help:

class Board
  def initialize(size=8)
    @size = 8
    @values = Array.new( size * size, 0 )
  end

  def [](x,y)
    @values[x*@size+y]
  end

  def []=(x,y,v)
    @values[x*@size+y]=v
  end
end

board = Board.new
tmp = board.dup
# manipulate tmp
board = tmp

If you store something other than integers in the cells you could add this
method:

  dup
    copy = super
    copy.instance_eval {@values.map! {|v| v.dup } }
    copy
  end

Cheers

    robert