From: Gunther Diemant <g.diemant@...>
Date: 2011-03-07T20:50:44+09:00
Subject: Re: basic programming question, help please

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You want a class method, not an instance method.

class Square
  def count1
    puts "I am instance method"
  end

  def self.count2
    puts "I am class method"
  end
end

sqr = Square.new

sqr.count1 #=> I am instance method
sqr.count2 #=> NoMethodError
Square.count1 #=> NoMethodError
Square.count2 #=> I am class method

On Mon, Mar 7, 2011 at 12:39 PM, Kaye Ng <sbstn26@yahoo.com> wrote:

> class Square
>  def initialize
>    if defined?(@@number_of_squares)
>      @@number_of_squares = @@number_of_squares + 1
>    else
>      @@number_of_squares = 1
>    end
>  end
>  def self.count
>    @@number_of_squares
>  end
> end
>
> a = Square.new    #would return 1
> b = Square.new    #would return 2
> puts Square.count #2 would be printed on the screen
>
> --------------------------------------------------------------------
>
> My question is: why is the "self" necessary in "def self.count".
> I don't understand the logic behind it.
>
> (I know that I can also type "def Square.count" instead of "def
> self.count")
>
> Thanks guys!
>
> --
> Posted via http://www.ruby-forum.com/.
>
>

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