From: Lauren Buckland <bucklandlo@...>
Date: 2011-02-05T15:03:01+09:00
Subject: Re: variables and scope

You are getting a -1 because you are using local variables. Thus, the n within your def is not the same as the n within your class.
Since you declared n to be -1 in your def, that is what your program responded with, a -1.
You need to initialize an instance variable that will be available throughout the class.

You can also make your code more utilitarian with a parameter value that can be changed any time you create a new instance.
Try the following:

class Test

  def initialize(n)
    @n = n
  end

  def pt
    puts "hi there"
    @n -= 1
  end
end

t = Test.new(100)
puts t.pt

This way, you are not tied down to the value 100, but can use any value you want.
I am new at this game and just taking the baby steps, but this seemed to work.

Lauren



On Feb 5, 2011, at 12:15 AM, Stu wrote:

> take note of the usage of @ for scope as well as the special
> initialize method used as a constructor for the object.
> 
> also note note you common bug/mistake. Your where setting n to
> negative one. you need to use n = n + -1 or shorthand version below is
> n += -1
> 
> class Test
>  def initialize
>  @n = 100
>  end
> 
>  def pt
>    p "hi there"
>    @n += -1
>  end
> end
> 
> t = Test.new
> puts t.pt
> 
> If you would like to know more have a look at attr_* in ruby
> 
> Good luck with your classes
> 
> ~Stu
> 
> 
> On Fri, Feb 4, 2011 at 10:17 PM, Mike 1. <mike17931793@gmail.com> wrote:
>> Hi all,
>> 
>>  I would be asking my instructor this question be she is not available
>> on
>> the weekends...
>> 
>>  How do I make "n" available from anywhere inside the class? I need to
>> keep the values in n from call to call.
>> 
>>  When calling the method "pt", "n" acts as if it was not declared above.
>> 
>>  I get -1 instead of what I wish for ... 99.
>> 
>>  Thanks in advance,
>> 
>>  Mike
>> 
>> class Test
>> n=100
>> 
>>  def pt
>>   puts "hi there"
>>   n=-1
>>  end
>> 
>> end
>> 
>> t = Test.new
>> puts t.pt
>> 
>> --
>> Posted via http://www.ruby-forum.com/.
>> 
>> 
>