Object Orientated Concepts

Overview  The world is objects  Defining an object  Not a function, it’s a method  Lets inherit want we can  Objects don’t have ‘mains’  Look at some Java Code

The world is objects (pg 34)  Everything is an object.  They have values  Things can be done to them  In small groups, starting with the object of a car, what are some methods about the car?

How does Java know what an object looks like?  Class definition public class ExampleApp{ public static void main (Strings[] args){ //some main code } public void ExampleMeth{ //Some other code }

Not a function, it’s a method  Methods can be public or private  In C, all functions are public  They work on the object and sometimes accept inputs

Lets inherit want we can (pg. 31)  An object ‘cat’ is a subset of ‘animal’ hence cat inherits the traits of animal  A new object ‘mushroom’ might inherit some of the ‘animal’ superclass but would have some very different methods and instance variables

Objects don’t have ‘mains’(pg.38)  Objects don’t have a ‘main’  If there is a ‘main’ it should test the current object only

Lets look at some Java code in detail (pg. 39)  Take a few minutes to look over the code on page 39.

Things to remember  Java and C share some syntax  This can be tricky  When doing OOP, think of code as interacting objects rather than a program that does different tasks  OOP can lead to easier revisions later, but a lot of the worlds code is not OOP