Ruby

Singletons in ruby

class ShoppingCart
  attr_reader :items

  def initialize
    @items = []
  end

  def add_item(item)
    @items << item
  end

  def total_price
    @items.sum(&:price)
  end
end

class Item
  attr_reader :name, :price

  def initialize(name, price)
    @name = name
    @price = price
  end
end

item1 = Item.new("Book", 10)
item2 = Item.new("Shoes", 50)
item3 = Item.new("Headphones", 30)

cart1 = ShoppingCart.new
cart1.add_item(item1)
cart1.add_item(item2)

cart2 = ShoppingCart.new
cart2.add_item(item3)

puts "Cart 1 total price: $#{cart1.total_price}"
puts "Cart 2 total price (with tax): $#{cart2.total_price}"


class ShoppingCart
  attr_reader :items

  def initialize
    @items = []
  end

  def add_item(item)
    @items << item
  end

  def total_price
    @items.sum(&:price)
  end
end

class Item
  attr_reader :name, :price

  def initialize(name, price)
    @name = name
    @price = price
  end
end

item1 = Item.new("Book", 10)
item2 = Item.new("Shoes", 50)
item3 = Item.new("Headphones", 30)

cart1 = ShoppingCart.new
cart1.add_item(item1)
cart1.add_item(item2)

cart2 = ShoppingCart.new
cart2.add_item(item3)

def cart2.total_price
  @items.sum { |item| item.price * 1.2 }
end

puts "Cart 1 total price: $#{cart1.total_price}"
puts "Cart 2 total price (with tax): $#{cart2.total_price}"
