Beginner Ruby Elevator Program

  # ruby beginner elevator program
  
  
  # We might break this stuff up into more classes as the need to separate state and
  # behaviour of different entities emerges, for now we keep it simple and imagine
  # the state to be that of the building as a whole.
  #
  
  class Building
    GROUND_FLOOR = 0

    attr_reader :elevator_on_floor
    attr_accessor :elevator_target_floor

    def initialize
      @elevator_on_floor = GROUND_FLOOR
      @elevator_target_floor = GROUND_FLOOR
    end

    def call_elevator_to_floor( new_floor )
      # Check that the call floor is legal (in a real elevator you wouldn't have buttons for illegal floors but this elevator isn't real!
      # If the new floor is different to the current floor, tell the elevator where to go
    end

    def time_passes
      # Is the elevator on the floor it has been called to?
      # If not move it one floor towards the target floor
      # If the elevator has reached it's target floor, print a message
    end

    def output_state
      # print out where the elevator is
      # if the elevator isn't at it's target floor print out whether it's heading up or down
    end

  end

  my_building = Building.new

  #
  # This part is the "game"
  # 
  # On each move you can either call the elevator to a floor by typing in the floor number
  # or simply allow the elevator to carry on its journey. Use ^d to exit (do you know why that
  # works?)
  #

  while line = gets
    line.chomp!

    if line =~ /d+/
      my_building.call_elevator_to_floor( line.to_i )
    end
    
    my_building.time_passes
    my_building.output_state
  end