For students lecture

classes.rb

class Task
  attr_accessor :title, :completted

  def initialize(title)
    @title = title
    @completted = false
  end
end

class TodoList
  def initialize(tasks = [])
    @tasks = tasks
  end

  def add_task(text)
    @tasks << Task.new(text)
    @tasks.length
  end

  def toggle_task(id)
    @tasks[id - 1].completted = !@tasks[id - 1].completted
  end
end

requre 'date'

class User
  def born_on
    Date.new(1989, 9, 10)
  end
end

class UserDecorator < SimpleDelegator
  def birth_year
    born_on.year
  endkkkkkkkkkkkkkkkkkkkkkkkkkk
end

user = User.new
decorated_user = UserDecorator.new(user)
decorated_user.birth_year #=> 1989
decorated_user.born_on #=> #<Date: 1989-09-10 ((2447780j,0s,0n),+0s,2299161j)>

class Vehicle
  attr_reader :model

  def initialize(model)
    @model = model
  end

  def power_reserve
    raise NotImplementedError
  end
end

class Car < Vehicle
  attr_reader :fuel, :consumption

  def initialize(model, fuel, consumption)
    super(model)
    @fuel = fuel
    @consumption = consumption
  end

  def power_reserve
    @fuel / @consumption * 100
  end
end

class ElectricCar < Vehicle
  def initialize(model, amp_hour, volt, consumption)
    super(model)
    @capacity = amp_hour * volt
    @consumption = consumption
  end

  def power_reserve
    @capacity / @consumption * 100
  end
end

class VehicleDecorator < SimpleDelegator
  def kilometers_range
    "#{self.power_reserve} km"
  end
end

car = Car.new('Volvo', 50, 11)
decorated_car = VehicleDecorator.new(car)
decorated_car.kilometers_range

e_car = ElectricCar.new('Tesla', 237, 43, 1650)
decorated_e_car = VehicleDecorator.new(e_car)
decorated_e_car.kilometers_range


class Emoji
  def draw
    ""
  end
end

class Apple < Emoji
  def draw
    puts "🍏"
  end
end

class Snake < Emoji
  def draw
    puts "🐍"
  end
end


def print_collection(collection)
  collection.each { |entry| print "#{entry}, "}
end

print_collection([1,2,3,4])
print_collection(1..4)
print_collection({ a: 1, b: 2, c: 3, d: 4 })