change_calculator.rb

class ChangeCalculator
  QUARTER = 0.25
  DIME    = 0.10
  NICKEL  = 0.05
  PENNY   = 0.01
  COINS   = [QUARTER, DIME, NICKEL, PENNY]
  
  def calculate(x)
    remaining = x
    $h = COINS.inject({}) do |hash, coin|
      hash[coin] = (remaining / coin).floor
      remaining = remaining % coin
      hash
    end
  end

  def output(hash)
    hash.each {|value, num| printf("number of %1.2f coins = %d\n", value, num)}
  end

  def run(x)
    calculate x
    output $h
  end
end

if $0 == __FILE__
  n = 1.36
  ChangeCalculator.new.run(n)
end