use attr_reader methods instead of @instance_variables internally within a class

gistfile1.rb

# attr_reader methods
# √ 1 common way to access attribute value
# √ Easier to refactor into a calculated/facade attribute

# attr_reader methods 
class Person

  attr_reader :name, :date_of_birth
  
  def initialize(name:, date_of_birth:)
    @name = name
    @date_of_birth = date_of_birth
  end
  
  def greet
    puts "Hi, my name is #{name}"
  end
  
  def age
    Time.now.year - date_of_birth.year
  end
  
end

# instance vars
class Person

  attr_reader :name, :date_of_birth
  
  def initialize(name:, date_of_birth:)
    @name = name
    @date_of_birth = date_of_birth
  end
  
  def greet
    puts "Hi, my name is #{@name}"
  end
  
  def age
    Time.now.year - @date_of_birth.year
  end
  
end