Edexcel 4CP0
IGCSE Computer Science
Complete Notes
Comprehensive topic-by-topic notes aligned to the Edexcel IGCSE Computer Science (4CP0) specification. Clear explanations, worked examples and exam-ready summaries for every chapter.
All Topics
Select a chapter to start reading. Each page covers the full specification content with explanations, examples and key definitions.
Chapter 1
Problem Solving
Algorithms, trace tables, standard algorithms and computational thinking — decomposition and abstraction.
Algorithms
Bubble & Merge Sort
Binary & Linear Search
Decomposition
Abstraction
Chapter 2
Programming
Writing, testing and debugging programs. Data types, structures, operators, validation and subprograms.
Data Types
Operators
Validation
File Handling
Subprograms
Chapter 3
Data
Binary representation, number systems, data representation for images and sound, compression and encryption.
Binary & Hex
ASCII & Unicode
Images & Sound
Compression
Encryption
Chapter 4
Computers
Hardware components, CPU and the FDE cycle, logic gates, operating systems, software and programming languages.
CPU & FDE Cycle
Memory Types
Logic Gates
Software
Languages
Chapter 5
Communication & the Internet
Networks, protocols, topologies, cyber security threats and protections, the internet and WWW.
LAN & WAN
Protocols
Topologies
Cyber Attacks
Internet & WWW
Chapter 6
The Bigger Picture
Environmental, ethical and legal impacts of computing. Emerging technologies including AI and quantum computing.
Environmental
Privacy & Ethics
Licensing
AI & Quantum
Nanotechnology
Qualification
Edexcel International GCSE
Subject Code
4CP0
Paper 1
Problem Solving (written exam)
Paper 2
Principles of Computer Science
Languages
Python · C# · Java
Pseudocode
Edexcel standard (Appendix 5)
Exam Tips
1
Trace tables are your friend. Practice filling them in for loops and selection — they come up in nearly every Paper 1.
2
Learn the pseudocode syntax. Edexcel has its own command set. Use the exact keywords from Appendix 5 in all written answers.
3
Know your standard algorithms. Be able to write and trace bubble sort, merge sort, linear search and binary search from memory.
4
File size calculations. Memorise the formulas for images (width × height × colour depth) and sound (sample rate × bit depth × duration).
5
Cyber security definitions. Be precise — phishing, pharming, shoulder surfing and eavesdropping all have specific meanings. Don't confuse them.
6
Chapter 6 needs opinions. Ethical and environmental questions often ask you to evaluate and give reasons — practise writing balanced, specific answers.