This document discusses object orientation in software design. It explains that object-oriented programming languages like VB.NET, C++, and Java use a model where data and functionality are wrapped in objects or classes. These classes can manage data privately and inherit properties from other classes. For example, in a driving game the Car class would contain data like weight and functions like accelerate, while the FordEscort class would inherit from Car. This allows the Driver object to interact with any Car without knowing its specific model, which is called polymorphism. The relationships between classes are represented using UML diagrams.

1. Lecture 2
Object Orientation
James Uren
BIT204
Software Design

2. Lecture 2
Object Orientation
Object Orientated Software
Modern software languages (VB.NET, C++, Java) use the software model of
object orientation (OO). This means data and functionality are wrapped up in
objects (or classes) that can manage their data privately and inherit
properties from other objects.
The objects in software design will often take their names from the nouns in
the specification. For example, in a driving computer game, the Car object will
contain data like the car’s weight, and functionality like ‘Accelerate’. The
FordEscort object inherits these properties and implements the Car’s
functionality.
This means the Driver object that is calling on the Car, does not need to know
the model of the car. This is called polymorphism. Note that in this case it is
never possible to create a generic Car object as this class is abstract or
virtual.
Driver Has A Car
Is A
FordEscort
The above representation of OO software is called UML (Universal Modelling
Language).
In C it would be described like this:
class Driver
{
Driver() {} // Constructor
// (called when object is created)
~Driver() {} // Destructor
// (called when object is deleted)
Lecture 1: Software Fundamentals
BIT204: Software Design – James Uren
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