Maintainability

Maintainable code is code that can be read, understood, and fixed by other developers. There are a few best-practice techniques to help write maintainable code, including:

Comments

Comments should be used throughout the code to:
- Explain complex processes.
- Clarify the purpose of algorithms.
- Clarify the purpose of a subroutine, as well as its parameters and return type and value.

Indentation

It is good practice to keep indentation of code consistent throughout the code.
When a new block of code opens, it should be indented to the right.
When a block of code closes, it should return to the left.
This makes code easier to read by visualising the scopes involved.

Identifier names

Identifier names should be clear about their purpose. For example, which of the following two examples makes more sense:
- newBalance = oldBalance * INTEREST_RATE;
- a = b * c;

Code structure

Code should be well structured through the use of subroutines.
This allows people to identify a single subroutine that they need to reuse or work on.

Parameters vs global variables

It is good practice to pass data around the program using parameter passing rather than using global variables.
This is because passing parameters prevents other subroutines from unexpectedly changing the value of the variables.

Comments

Comments are lines of code that are ignored completely by the computer.

What are comments?

A comment is a line of code that is completely ignored by the computer.

Purpose of comments

Comments can be used to add description to your code to make it easier for other people to understand.
They can also be used to leave notes and reminders to yourself as you work on a complex program.

How to comment

To write a comment in most languages, you must use a special character which tells the computer to ignore the rest of the line:
- In Python, that character is a #.
- In C-style languages it is //.
The exact character depends on the language being used.

1Computer Systems

1.1Systems Architecture

1.1.1Architecture Introduction

1.1.2Von Neumann Architecture

1.1.3Fetch-Execute Cycle

1.1.4Factors Affecting CPU Performance

1.1.5Elements of Computer Systems

1.1.6Exam-Style Questions - Von Neumann Architecture

1.2Memory & Storage

1.3Computer Networks, Connections & Protocols

1.4Network Security

1.4.1Forms of Attack

1.4.2Malware

1.4.3Social Engineering

1.4.4Phishing

1.4.5Common Active Attacks

1.4.6Information Security

1.4.7SQL Injection

1.4.8Network Administration

1.4.9Protecting Against Malware

1.4.10Authentication & Passwords

1.4.11Encryption

1.4.12End of Topic Test - Networks

1.5Systems Software

1.5.1Types of System Software

1.5.2Operating Systems

1.5.3Operating System Managers

1.5.4File Management

1.5.5Device Management

1.5.6User Management

1.5.7Utility Software: Encryption & Defragmentation

1.5.8Utility Software: Data Compression & Backup

1.6Ethical, Legal, Cultural & Environmental Concern

1.6.1Open Source vs Proprietary Software

1.6.2Licensing Issues

1.6.3Ethical Issues

1.6.4Ethical Issues 2

1.6.5Exam-Style Questions - Ethical Issues

1.6.6Legal Issues

1.6.7Legal Issues 2

1.6.8Freedom of Information Act (2000)

1.6.9Cultural Issues

1.6.10Environmental Issues

1.6.11Positive Environmental Impact

1.6.12Privacy Issues

1.6.13Stakeholders

1.6.14End of Topic Test - Software & Issues

2Computational Thinking, Algorithms and Programming

2.1Algorithms

2.1.1Computational Thinking

2.1.2Algorithmic Thinking

2.1.3Pseudocode & Flow Diagrams

2.1.4Interpreting & Correcting Algorithm

2.1.5Completing Algorithms

2.1.6Search Algorithms

2.1.7Binary Search

2.1.8Overview of Sort Algorithms

2.1.9Bubble Sort & Insertion Sort

2.1.10Merge Sort

2.1.11Exam-Style Questions - Sorting Algorithms

2.2Programming Fundamentals

2.2.1Fundamentals

2.2.2Program Flow 1

2.2.3Program Flow 2

2.2.4Arithmetic & Relational Operators

2.2.5Boolean Operators

2.2.6Data Types

2.2.7Arrays

2.2.8Strings

2.2.9File Handling

2.2.10Structuring Data

2.2.11End of Topic Test - Programming

2.2.12Exam-Style Questions - Translation

2.3Producing Robust Programs

2.3.1Defensive Design Considerations

2.3.2Defensive Design Considerations 2

2.3.3Maintainability

2.3.4Testing

2.3.5Test Plans

2.3.6Error Types

2.3.7End of Topic Test - Programming

2.3.8Exam-Style Questions - Testing

2.4Boolean Logic

2.4.1Computational Logic

2.4.2Boolean Logic

2.4.3Boolean Operators

2.4.4Grade 9 - Logic

2.5Programming Languages & IDEs

2.5.1High-Level vs Low-Level Languages

2.5.2Translation - Compliers & Interpreter

2.5.3Translation - Assemblers

2.5.4Integrated Development Environments

2.5.5Exam-Style Questions - Translation

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