CSC/ECE 517 Fall 2011/ch7 7a or
Wiki Chapter: CSC/ECE 517 Fall 2011/ch7 7a or
7a. Representing money. Skrien Chapter 6 gives an example of a class that can be used to represent money. But how is it done in real programs? Investigate, and report on the advantages and disadvantages of other approaches vs. Skrien's.
Introduction
Money is very important to people worldwide and is something that often must be represented in computer programs. This raises the question of how money should be represented, which can vary from program to program. There is much to be considered such as string formatting, the way money is used, and the variety of different currencies in the world. In Chapter 6 of Skrien's Object-Oriented Design Using Java, he suggests an implementation that represents money as a class, but there are other approaches that can be taken, each with their respective advantages and disadvantages.
Properties of Money
Money has certain properties and uses that must be considered in implementation.
Responsibilities/Using Money
The following are ways in which a representation of money should be able to be used [1]:
- To represent a positive or negative amount of money.
- Possibly representing multiple components of a currency - i.e. dollars and cents.
- Possibly representing amounts of multiple currencies - i.e. a mix of US Dollars, euros, and yen.
- Addition, subtraction, multiplication, and division.
The degree to which of the above must be met will depend on the depth of the implementing project.
Different Currencies
Immutable vs. Mutable
Possible Representations
Floating Point Number
Two Integers
One Integer, Implied Decimal Point
Class
Abstract Class
Single Class
Mixed Money
Using an Interface
Handling Conversion
Resources
- Need to go through these for information
- PDF from class lecture
- Java's Currency class docs
- A standalone class to tackle the problem (in Java)
- Representing money (Java)
- Working with money in Java
- Time and Money Java project - doesn't seem to have much documentation, though
- Joda Money class library for Java
- BigDecimal and Your Money (a criticism of using BigDecimal format)
- Tutorial on using BigDecimal
- JUnit Test Infected: Programmers Love Writing Tests (has a Money class example
- Currency Internationalization (i18n), Multiple Currencies and Foreign Exchange (FX) -nothing programming-wise, but a good overview of the considerations for currency
- Yet Another C++ Money Class
- Representing currencies (txt document with example and details)