For given dollar amount make change (USA)

make_change.rb

#!/usr/bin/env ruby

def make_change(change_amount)
  #denominations to use. Could easily be made a parm.
  #Note that these are integers, not floats
  denominations = {
    Penny: 1,
    Nickel: 5,
    Dime: 10,
    Quarter: 25
  }
 #Sort by value desc
 sorted_denominations = denominations.sort_by {|k,v| -v}.to_h
 #convert number into integer to avoid rounding errors
 temp_amount = change_amount * 100
 results_hash = {}
 sorted_denominations.each do |coin_label, coin_value|
   coin_frequency = (temp_amount / coin_value).round
   results_hash[coin_label] = coin_frequency unless coin_frequency.zero?
   temp_amount -= (coin_frequency * coin_value)
 end
 return results_hash
end