Object-Oriented Languages

Test yourself

Object-Oriented Languages

Object-oriented programming allows us to model real-world objects and manipulate them easily.

Object-oriented programming

In object-oriented programming, most real-world objects, like cars, can be modelled.
Each object is an instance of the class. Objects contain:
- Attributes: things we store about them e.g. the make and model of the car.
- Methods: things the object can do e.g. starting the engine or indicating to turn.

Classes

A class forms a blueprint that we can use to instantiate (create) an object.
A car class could be instantiated for every car ever made.
Each object would have the same behaviours, but slightly different values in their attributes.

Inheritance

We can define a subclass from what we call the 'super class'.
- These are sometimes known as child class and parent class.
In inheritance, the subclass inherits all of the attributes and methods of the superclass.
The subclass can have its own attributes and methods.

Example

If we had a vehicle super class, we could have a subclass of car that would inherit all of the attributes and methods of the vehicle class.
The car subclass could add additional attributes such as colour and methods such as indicate_left that do not apply to the vehicle super class.

Classes

A class is a blueprint for creating objects.

What is a class?

A class is a blueprint for creating an object.
One class will often represent one type of real-world object.
- For example: in a snooker game you might have a 'Ball' class.

What is inside a class?

A class contains two main components:
- Attributes: these are variables which describe the object.
- Methods: these are subroutines which allow the object to perform actions.

Classes in Java

Classes have different levels of visibility.
In Java, classes are created using the class keyword.
- These classes can be made public (can be used in any part of the program) using the public class keywords.
The image above shows a Java class.

Objects

Objects are made from classes.

Creating an Object

Objects are created from classes.
To create an object we use the keyword new and the name of the class:
- MyClass myObj = new MyClass();

Accessing attributes

If an attribute of an object is public, then it can be accessed from outside the class.
Object attributes are accessed using dot notation:
- int attr = myObj.attr;

Calling methods

If a method of an object is public, then it can be accessed from outside the class.
Object methods are accessed using dot notation:
- myObj.doSomething();

1Components of a Computer

1.1Structure & Function of the Processor

1.1.1Structure of the CPU

1.1.2Fetch, Decode, Execute Cycle

1.1.3Factors Affecting CPU Performance

1.1.4CPU Architecture

1.2Types of Processors

1.2.1CISC & RISC

1.2.2Multicore & Parallel Cores

1.3Input, Output & Storage

1.3.1Computer Systems

1.3.2Magnetic Storage

1.3.3Optical Storage

1.3.4Types of Optical Storage

1.3.5Types of Memory

1.3.6Flash Memory

1.3.7Virtual Memory

2Software & Software Development

3Exchanging Data

4Data Types, Data Structures & Algorithms

4.1Data Types

4.1.1Data Types

4.1.2Arrays & Strings

4.1.3Representing Numbers

4.1.4Binary Arithmetic

4.1.5Hexadecimal

4.1.6Converting Binary Numbers

4.1.7Floating Points in Binary

4.1.8Floating Point Arithmetic

4.1.9Bitwise Manipulation

4.1.10Character Sets

4.2Data Structures

4.2.1Arrays, Linked Lists & Queues

4.2.2Graphs, Hash Tables & Stacks

4.2.3Trees

4.3Boolean Algebra

4.3.1Computational Logic

4.3.2Boolean Logic

4.3.3Karnaugh Maps

4.3.4Boolean Identities

4.3.5Flip Flops & Adder Circuits

5Legal, Moral, Cultural & Ethical Issues

5.1Computing Related Legislation

5.1.1Data Protection Act (1998)

5.1.2Computer Misuse Act (1990)

5.1.3Copyright Designs and Patents Act (1988)

5.1.4Regulation of Investigatory Powers Act (2000)

5.2Moral & Ethical Issues

5.2.1Online Activity Tracking

5.2.2Censorship

5.2.3Cultural Issues

5.2.4Environmental Issues

5.2.5Layout, Colour Paradigms & Character Sets

6Elements of Computational Thinking

6.1Thinking Abstractly

6.1.1Abstraction

6.2Thinking Procedurally

6.2.1Decomposition

6.3Thinking Logically

6.3.1Pseudocode & Flow Diagrams

7Problem Solving & Programming

7.1Programming Techniques

7.1.1Programming Fundamentals

7.1.2Modularity

7.2Programming Construction

7.2.1Integrated Development Environments

7.2.2Testing

8Algorithms

8.1Algorithms

8.1.1Interpreting, Correcting & Completing Algorithm

8.1.2Sort Algorithms

8.1.3Insertion & Merge Sort

8.1.4Search Algorithms

Jump to other topics