Rework on uni year one assignment question. Given any amount in cents, calculate changes

gistfile1.rb

module ChangeMachine

  class IdiotEncountered < StandardError; end

  AVAILABLE_UNITS = [10000, 5000, 2000, 1000, 500, 200, 100, 50, 20, 10, 5]

  def self.show_me_the_money(dollar_in_cents)
    raise IdiotEncountered, "You are an idiot, no such amount in AUS..." unless dollar_in_cents % 5 == 0

    dispense(dollar_in_cents)
  end

  def self.dispense(dollar_in_cents)
    return {} if dollar_in_cents == 0

    unit = AVAILABLE_UNITS.select{|u| u <= dollar_in_cents}.max

    {unit => (dollar_in_cents / unit)}.merge(dispense(dollar_in_cents % unit))
  end
end

puts ChangeMachine.show_me_the_money(37500).inspect

Original version written in 2001 :) My first ever program I think

//Name: Jim Li
//Subject: CS108
//Program: Assignment 1
//File name: Change.java
//Date: 19/03/2001
//Program description: This is a program that will give the use a smallest number of change of coins.


import java.io.*;

public class Change
{
   public static void main (String[] args) throws IOException
   {
      BufferedReader stdin=new BufferedReader (new
      InputStreamReader(System.in));
      String x;
      System.out.println("Input the amount of change in cents");
      System.out.println("between 0 cents and 499 cents");
      x=stdin.readLine();
      int y = Integer.parseInt(x);
      if(y>=0&&y<500)
      {
         int a = (int)(y/200);
         int b = (int)((y-200*a)/100);
         int c = (int)((y-200*a-100*b)/50);
         int d = (int)((y-200*a-100*b-50*c)/20);
         int e = (int)((y-200*a-100*b-50*c-20*d)/10);
         int f = (int)((y-200*a-100*b-50*c-20*d-10*e)/5);
         int g = (int)((y-200*a-100*b-50*c-20*d-10*e-5*f)/1);
         int h = a+b+c+d+e+f+g;   
         System.out.print("$2 coins   ");
         System.out.println(a);
         System.out.print("$1 coins   ");
         System.out.println(b);
         System.out.print("50 cents coins   ");
         System.out.println(c);
         System.out.print("20 cents coins   ");
         System.out.println(d);
         System.out.print("10 cents coins   ");
         System.out.println(e);
         System.out.print("5 cents coins   ");
         System.out.println(f);
         System.out.print("1 cents coins   ");
         System.out.println(g);
         System.out.print("Total Number of Coins   ");
         System.out.println(h);
      }
      else
         System.out.println("input error");

  }
}

I like your original version better :P

@tommyli that's the exact version I submitted ... Now thinking about it, tutoring is hard work. It's like a torture EVERY single time you mark a year one student assignment... well most of them anyway