cashier.rb

#Cashier.rb

require './register.rb'
require 'pry'

cashier = Register.new

while  cashier.get_sale_price != "done"
	cashier.add_sale_price_to_list
	cashier.calculate_sub_total
	puts "Subtotal: $" + cashier.sub_total.to_s
end

cashier.list_items

puts "The total amount due is: $" +  cashier.sub_total.to_s

cashier.get_amount_tendered

if cashier.validate_amount?
	cashier.calculate_change
	puts "=========Thank You!========="
	puts "The total change due is $" + cashier.change.to_s
else
	puts "WARNING: Customer still owes #{sprintf('$%0.2f', (cashier.sub_total.to_f-cashier.amount_tendered.to_f))}! Exiting..."
end

register.rb

#Register.rb

class Register
	attr_accessor :sale_price, :items, :sub_total, :amount_tendered, :change	
	def initialize
		@items = []
	end

	#VAIDATIONS
	
	def validate?(object)
		if  object == "done" || (object !~ /\A\$?\d+(\.\d{1,2})?\z/) == false
			return true
		else
			return false
		end
	end

	def validate_amount?
		@amount_tendered.to_f  > @sub_total.to_f	
	end

	#Other Methods

	def get_sale_price
		puts "What is the sales price?"
		@sale_price = gets.chomp
		return "done" if @sale_price == "done"
		get_sale_price if validate?(@sale_price) == false
	end

	def get_amount_tendered
		puts "What is the amount tendered?"
		@amount_tendered = gets.chomp
	end

	def add_sale_price_to_list
		@items << @sale_price.to_f
	end

	def list_items
		puts "Here are your item prices?"
		@items.each do |i|
			puts "$" + i.to_s
		end
	end

	def calculate_sub_total
		@sub_total = 0
		@items.each do |i|
			@sub_total +=i.to_f 		
		end					
	end

	def calculate_change
		@change = @amount_tendered.to_f - @sub_total.to_f
	end
end