08_object_state_2.rb

# Programming exercise 5.8: Writing Classes - part 2
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# Tutorial: http://ruby-for-beginners.rubymonstas.org/objects.html         #
# Tutorial: http://ruby-for-beginners.rubymonstas.org/writing_classes.html #
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class Sheep
  def initialize
    @hungry = 3
    @tired = true
  end

  def wake_up
    @tired = false
    puts "Yaaaawwn. Good morning! ;)"
  end

  def sleeping?
    @tired
  end

  def hungry?
    @hungry > 0
  end

  def eat_grass
    if sleeping?
      puts "I'm still asleep! You have to wake me up!"
    else

      if hungry?
        puts "Mmmh, yummy grass!"
        @hungry = @hungry - 1
      end

      if hungry?
        puts "I'm still hungry! I want to eat more grass."
      else
        puts "Now I'm full!"
      end
    end
  end
end

# This is just another exercise on object oriented programming
# Here we have to call certain methods on the object to reach our goal
# You don't have to change the class' definition

# Okay, so we are creating a new instance of class sheep here
sheep = Sheep.new
p sheep
# TODO: Feed the sheep until it's full!
# TODO: If we call sheep.eat_grass, the sheep will tell us it's still sleeping
# TODO: What method do we have to call on the sheep first??
# => Siehe folgende Zeile
sheep.wake_up
p sheep
# TODO: So, which methods, in which order and how often do we have to call them?
sheep.eat_grass
p sheep
sheep.eat_grass
p sheep
sheep.eat_grass
p sheep
# TODO: Can you imagine how the objects state changes when you call certain methods?
# => Erst Schaf mit sheep.wake_up aufwecken, dann 3x mit sheep.eat_grass sättigen.
# TODO: Call 'p sheep' between your steps
p sheep
# TODO: So you can see how the instance variables of the sheep change