struct.rb

class UserAddressBook
  attr_accessor :user_id, :address_book_entry

  def initialize(user_id, address_book_entry)
    @user_id = user_id
    @address_book_entry = address_book_entry
  end
end

address_book1 = UserAddressBook.new(42, 'test')
address_book2 = UserAddressBook.new(42, 'test')

p address_book1 == address_book2 # false

UserAddressBookStruct = Struct.new(:user_id, :address_book_entry)

struct1 = UserAddressBookStruct.new(user_id: 42, address_book_entry: 'test')
struct2 = UserAddressBookStruct.new(user_id: 42, address_book_entry: 'test')

p struct1 == struct2 # true