Introduction to OOP

car.rb

# opening a class statement
class Car
  # Getter / Reader
  # attr_reader :color # => defines a getter
  # attr_writer :color # => defines a setter
  attr_accessor :color # => defines both

  # This is the constructor
  # will be called on .new
  def initialize(color = "blue")
    puts "Creating a car instance..."
    # defining an instance variable
    @engine_started = false
    @color = color
    @speed = 0
  end

  # Getter / Reader
  # def color
  #   @color
  # end

  # Setter / Writer
  # def color=(color)
  #   @color = color
  # end

  # Public Interface
  def engine_started?
    @engine_started
  end

  def start_engine
    start_fuel_pump # call to a private method
    spark_plug
    @engine_started = true
  end

  def accelerate
    @speed += 50

    if @speed < 150
      puts "VRUMMMMM..."
      puts "The current speed is #{@speed}"
    else
      puts "You fool! You crashed!"
    end
  end

  def brake
    @speed -= 50
    puts "Breaking...."
    puts "The current speed is #{@speed}"
  end

  private

  def start_fuel_pump
    puts "Pumping fuel into the engine..."
  end

  def spark_plug
    puts "Combustion explosion..."
  end
end

interface.rb

require 'byebug'

require_relative 'car'

my_car = Car.new
your_car = Car.new


# ask object for internal data
my_car.engine_started?

# user one of the behaviours of the instance
# my_car.start_engine
# my_car.start_fuel_pump

red_ferrari = Car.new("red")

puts "My Ferrari is #{red_ferrari.color}" # => "red"

red_ferrari.color = "orange"

puts "My Ferrari now is #{red_ferrari.color}"

2.times do
  red_ferrari.accelerate
end

red_ferrari.brake