heresthechange.rb

class Cashier

  @@tokens = {100 => 1, 200 => 4, 500 => 2, 1000 => 2, 2000 => 2, 5000 => 2, 10000 => 2, 20000 => 1, 50000 => 0, 100000 => 0}
  
  def givemychange(ch)
    @change = []
    p = @@tokens.keys.sort.reverse
    p.each do |money|
      temp = ch / money
      next if temp == 0 or @@tokens[money] == 0
      while temp > 0
        @change << money
        puts "ambil " + money.to_s
        temp -= 1
        @@tokens[money] -= 1
        if @@tokens[money] == 0
          puts "lembar "+ money.to_s + " habis!!!"
          t = temp * money
          temp = 0
        end
      end
      ch %= money
      ch = ch.to_i + t.to_i
      puts "tinggal " + ch.to_s
      break if ch == 0
      retry
    end
    @change
  end

  def ipaywith(h,total)
    payment = 0
    puts "tagihan = " + total.to_s
    puts "dibayar dengan uang : "
    h.each do |money, sum|
      puts money.to_s + ": " + sum.to_s + " lembar"
      payment += money * sum
    end
    puts "= "+ payment.to_s
    ch  = payment - total
    return "bayarnya kurang..." if ch < 0
    puts "kembali = " + ch.to_s
    h.each do |m, s|
      @@tokens[m] += s
    end
    givemychange ch
  end

  def tokens
    @@tokens
  end

end

cash = Cashier.new
puts cash.ipaywith({5000 => 4}, 18000)
puts cash.ipaywith({2000 => 3, 5000 => 1}, 10000)
puts cash.ipaywith({50000 => 1}, 2300)
puts cash.ipaywith({100000 => 1}, 13500)
puts cash.ipaywith({50000 => 1, 10000 =>2, 1000 => 5}, 75000)
puts cash.ipaywith({20000 => 2}, 34300)
puts "sisa "
cash.tokens.each do |m,s|
  puts m.to_s + " = " + s.to_s
end