Ruby OOP example

person.rb

class Person
  def initialize name, dob
    @name = name
    @dob = dob
  end

  def age
    (Time.now - @dob) / (365 * 24 * 60 * 60)
  end

  def introduce_yoself
    print "Hey, I'm #{@name} and I was born #{age} years ago.\n"
  end
end

maxxx = Person.new("Max", Time.new(1988, 9, 11))
maxxx.introduce_yoself
# which prints
# "Hey, I'm Max and I was born 23.986193869358075 years ago."

class CoolDude < Person
  def initialize name, dob, nickname
    super name, dob
    @nickname = nickname
  end

  def introduce_yoself
    print "Yo, they call me '#{@nickname}'."
  end
end

waltr0x = CoolDude.new("Walter", Time.new(1987, 9, 29), "The Laser")
# we've still got this function
print waltr0x.age
# 24.939627905041938
waltr0x.introduce_yoself
# "Yo, they call me 'The Laser'."