car.rb

class Car

  def initialize(color)
    @color = color
    @engine_started = false
  end

  # allow you to read instance variable
  def color
    return @color
  end

  # shortcut for reading instance variable
  attr_reader :engine_started, :color

  # modify state of instace variable
  def color=(color)
    @color = color
  end

  # shortcut for modifying an instance variable
  attr_writer :color

  # shortcut for attr_reader && attr_writer
  attr_accessor :color, :engine_started

  # calls private methods not in the public interface of this class
  def start
    ignit
    makes_a_noise
    @engine_started = true
  end

  private #Everything under is in the private interface of this class, not available in the outside world

  def ignit
    puts "Ignit"
  end

  def makes_a_noise
    puts "vroom vroom"
  end
end

demo.rb

require "pry-byebug" #require the pry-byebug gem

def full_name(first, last)
  first_name = first.capitalize
  binding.pry # breakpoint to indicate where the program is gonna pause
  last_name = last.capitalize
  name = "#{first_name} #{last_name}"
  return name
end

full_name("bar", "ben")


# keywords for pry-bye bug :
# next : execute the next line
# continue: execute the code until the next breakpoint or the end of the method

sports_car.rb

class SportsCar
end