README.md

Poppin' Bottles

You've just been hired at Lighthouse Markets, a reputable (and thoroughly fictional) grocery store chain. One of the primary features of Lighthouse Markets is their recycling program on pop bottles. Here is how the program works:

• For every two empty bottles, you can get one free (full) bottle of pop
• For every four bottle caps, you can get one free (full) bottle of pop
• Each bottle of pop costs $2 to purchase

Given these parameters, write a program so that you can figure out how many total bottles of pop can be redeemed given a customer investment.

Task 1

Figure out the algorithm that will calculate this. For example, given a $20 investment, the customer will get 10 bottles of pop. That gives a supply of both bottles and bottle caps that can be used to redeem for further bottles, which will then produce a further supply for recycling.

Task 2

Write a REPL that will prompt the user for the amount (in dollars) that the customer is going to spend. The REPL will then calculate the total number of bottles that the customer will receive and prompt for the next customer's amount.

Task 3

Enhance the output of your program so that once the amount has been given, it provides a breakdown of how many bottles were purchased, how many were obtained through bottle recycling, and how many were obtained through bottle cap recycling.

Task 4

Add to the output, so that the program will tell the customer how many bottles and bottle caps they will have left over. We have to upsell the customer on buying more pop after all!

TIP! Iterate, Iterate, Iterate

You hear this from us all the time, but build your code incrementally. Build it in small steps, and make sure you are confident and comfortable that the code is functioning correctly before you move on to the next step.

TIP! @instance variables

Your use of instance variables for keeping track of different variables will be very important here.

BONUS!

Write this same algorithm using recursion.

account.rb

class Account
  attr_accessor :bottlecaps
  attr_accessor :empties
  attr_accessor :current_redemptions

  def initialize
    @bottlecaps = 0
    @empties = 0
    @current_redemptions = 0
  end

  def add_bottles(num)
    @bottlecaps += num
    @empties += num
  end

  def lose_bottles(num)
    @bottlecaps -= num
    @empties -= num
  end

  ## Redeems bottles once
  def redeem_bottles
    new_bottles = @bottlecaps/4 + @empties/2
    @current_redemptions += new_bottles

    current_bottlecaps = @bottlecaps
    current_empties = @empties

    @bottlecaps = @bottlecaps % 4
    @empties = @bottlecaps % 2

    add_bottles(new_bottles)
  end

  ## Redeems bottles as long as they can be redeemed. Returns total number of redemptions.
  def redeem_all
    while @bottlecaps >= 4 || @empties >=2
      redeem_bottles
    end

    @current_redemptions
  end

end

recycling_program.rb

class RecyclingProgram 

  def initialize(name)
    @name = name
    @open = false
    @bottlecaps = 0
    @empties = 0
  end

  def open 
    @open = true
    while @open
      open_for_business 
    end
  end

  ## open for business!
  def open_for_business
    puts "Welcome to #{name}."
    puts "BUY -- add new bottles to your account"
    puts "REDEEM -- redeem bottles: lose and add bottles to your account"
    puts "CHECK -- check bottles in account"
    puts "BYE -- close recycling program"
    input = gets.chomp.upcase
    handle(input)
  end

  def handle(input)
    case input
    when "BUY" then ui_buy
    when "REDEEM" then ui_redeem
    when "CHECK" then ui_check
    when "BYE" then shut
    else
      puts "Input not recognised!"
    end
  end

  def shut
    puts "Thanks for recycling!"
    @open = false
  end

  def ui_buy
    puts "How much would you like to spend on bottles today? e.g. 20 for $20"
    investment = gets.chomp
    buy_pop(investment)
    display_account ## TODO
  end


  def buy_pop(dollars)
    new_bottles = dollars/2
    @bottlecaps += new_bottles
    @empties += new_bottles
  end

  def redeem
    redeem_total = 0
    new_bottles = 0

    new_bottles += @bottlecaps/4
    @bottlecaps = @bottlecaps % 4

    new_bottles += @empties/2
    @empties = @empties % 2

    @bottlecaps += new_bottles
    @empties += new_bottles
    redeem_total += new_bottles

    while @bottlecaps > 4 || @empties > 2
      redeem
    end

    redeem_total
  end

end

lighthouse = RecyclingProgram.new("Lighthouse Markets")
puts "#{lighthouse.buy_pop(20)}"
puts "#{lighthouse.redeem}"

simple_program.rb

require_relative 'account.rb'

class SimpleProgram
  @running = false

  def run
    @running = true
    while @running
      cash_register
    end
  end

  def cash_register
    puts "How much $$ would you like to spend?"
    investment = gets.chomp.match('\d+')
    investment = investment[0].to_i
    customer = Account.new
    customer.add_bottles(investment/2)
    puts "If you spend $#{investment}, you will get a total of #{customer.redeem_all} bottles through our recycling program"
    puts "You will then have #{customer.bottlecaps} bottlecaps and #{customer.empties} empty bottle left."
  end


end



lighthouse = SimpleProgram.new
lighthouse.run