Suppose we are programming a vending machine. When a customer inserts money and purchases a product from our machine, we might owe them change. The idea behind this kata is simple: given an amount of money, return to the user the proper amount of change (with right number of coins, in USD currency). Essentially, make change for the user.
Let's see how we aim to use this class when we're done.
# Initialize the object we're going to use to make change
mc = MakeChange.new
# Pass in the amount of money we want change for
mc.change(83)
# Our program's output
=> [1 => 3, 5 => 1, 10 => 0, 25 => 3]Notice that the sample output is a hash. The hash keys are the values (integers) of each coin denomination. In this example, we are getting back 3 pennies, 1 nickel, and 3 quarters.
If we implement this and still have time, let's also add support for whole dollars.
mc = MakeChange.new
mc.change(104)
=> [1 => 4, 5 => 0, 10 => 0, 25 => 0, 100 => 1]The following resources will help ramp you up for the dojo. You should by no means feel like you need to know (or understand) all (or even most) of this information. At the dojo, we're all here to help each other.
- If you're new to Ruby, I recommend going through the http://tryruby.org tutorial before the meeting.
- RSpec (testing) cheat sheet. I will have copies for the meeting, but you may want to review. http://www.anchor.com.au/blog/2013/03/updated-rspec-cheatsheet/
This will be updated after the dojo!