oop - Confused by Ruby's class constructors and virtual accessors -

as had limited exposure programming , in python , c++, find ruby refreshing , enjoyable language, having little trouble understanding ruby's use of class constructors , virtual accessors, , not considered constructor , whether understand virtual accessors correctly.

here's example (credit due pragmatic bookshelf, programming ruby 1.9 & 2.0):

class bookinstock   attr_accessor :isbn, :price # part of class constructor?    def initialize(isbn, price) # , initialize method part of constructor or regular method?     @isbn = isbn      @price = price   end    def price_in_cents      integer(price*100+0.5)   end    def price_in_cents=(cents) # 'virtual accessor' method, trough able update price down road...?     @price = cents / 100.0    end end  book = bookinstock.new('isbn1', 23.50) puts "price: #{book.price}" puts "price in cents: #{book.price_in_cents}" book.price_in_cents = 1234 # here updating value 'virtual accessor' declared earlier, understand puts "new price: #{book.price}" puts "new price in cents: #{book.price_in_cents}" 

thanks understanding piece of code.

1 attr_accessor :isbn, :price # part of class constructor?

this line keep concept of access private member through method philosophy. it's in effect equivalent declare 2 private members , getter , setter methods, has nothing constructor.

2 def initialize(isbn, price) # , initialize method part of constructor or regular method?

to put in easy way, constructor. method called upon 'new' keyword

3 def price_in_cents=(cents) # 'virtual accessor' method, trough able update price down road...?

it's alternative of price= method, takes argument in different format, price= method setter method automatically generated question line 1.

4 book.price_in_cents = 1234 # here updating value 'virtual accessor' declared earlier, understand it

keep in mind feels assigning variable accessing setter method, in consistent concept reflected in question line 1 , 3.