From: Chuck Remes <cremes.devlist@...>
Date: 2011-08-22T23:05:57+09:00
Subject: Re: New to Ruby some problems


On Aug 22, 2011, at 8:53 AM, Chuck Remes wrote:

> On Aug 22, 2011, at 8:32 AM, jack jones wrote:
> 
>> I am new to Ruby, My mother tongue is C++ .. I have too many problems I
>> hope you'd help me with that in the 2 short attached files .. thank you
>> very much :)
>> 
>> Attachments:
>> http://www.ruby-forum.com/attachment/6536/2Dto1D.rb
>> http://www.ruby-forum.com/attachment/6537/Complex.rb
> 
> First, fix the syntax errors. You are missing commas in some of your method definitions and adding spaces after the '@' character in your instance variables. There may be other issues, but the Ruby runtime should point them out to you when you try to load and execute your code.
> 
> To answer your question about adding a setter/getter for the MATRIX class, you could define #[] and #[]= for that purpose to delegate to your @array ivar.
> 
> e.g.
> 
> def [](index)
>  @array[index]
> end
> 
> def []=(index, value)
>  @array[index] = value
> end

Sorry, I didn't read the problem closely enough (too early in the morning!). You need to pass a ROW and COLUMN to set or get a value in your matrix instead of just a single value like I posted above.

Something like this might be a good start (untested).

class Matrix
  def initialize(rows, cols)
    @array = []
    @rows, @cols = rows, cols
  end

  def set(x, y, value)
    @array[index(x, y)] = value
  end

  def get(x, y)
    @array[index(x,y)]
  end

 private

  def index(x, y)
    (x * @cols) + y
  end
end