From: Love U Ruby <lists@...>
Date: 2013-02-18T03:09:15+09:00
Subject: What is Ruby's default constructor?

Hi,

I wrote the below class :

>>  class Adder
>>
?>    def initialize(my_num)
>>      @my_num = my_num
>>    end
>>
?>  end
=> nil

>> ob = Adder.new
ArgumentError: wrong number of arguments (0 for 1)
  from (irb):3:in `initialize'
  from (irb):8:in `new'
  from (irb):8
  from /usr/bin/irb:12:in `<main>'

#~~~> Here it is not allowing the creation of object.Even does not
allowing automatic call to its default constructor which it does when a
class has been defined without "initialize" method.

>> ob = Adder.new(10)
=> #<Adder:0x000000013df828 @my_num=10>

#~~~> here it is OK. and it should be.

#~~> then in the below class how object is created, what constructor it
has called?

>> class A
>> p "hi"
>> end
"hi"
=> "hi"
>> ob = A.new
=> #<A:0x0000000122ff50>
>>

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