Computing

Algorithm complexity measures how the running time or memory usage of an algorithm grows as the size of its input increases. Big-O notation is the standard way to express this.

Space complexity describes how much memory an algorithm needs relative to its input size. Alongside time complexity, it helps you evaluate whether an algorithm is practical for a given situation.

Time complexity describes how the running time of an algorithm grows as the input size increases. Using Big O notation, you can compare algorithms and predict which will perform better on large datasets.

Drawing a flowchart means turning an algorithm into a clear visual diagram using the correct symbols, decision paths, and loop structures. A well-drawn flowchart communicates logic better than code alone.

Flowchart symbols are standardised shapes used to represent different types of steps in an algorithm. Learning the standard symbols lets you read and draw flowcharts clearly and consistently.

A flowchart is a visual diagram that uses standard shapes and arrows to represent the steps and decisions in an algorithm or process.

Study of problem-solving approaches, algorithm design, and computational complexity analysis.

Pseudocode structures — sequence, selection, and iteration — are the three building blocks used to express any algorithm. Mastering them lets you plan solutions to complex problems clearly.

Pseudocode is an informal, plain-English way of describing an algorithm's steps without worrying about the exact rules of any programming language.

Pseudocode is an informal way of describing an algorithm using plain language and programming-like structure. It lets you plan your logic before worrying about the syntax of a real programming language.

Binary search finds a target value in a sorted list by repeatedly halving the search space. It is dramatically faster than linear search for large datasets.

Linear search checks each item in a list one by one until it finds the target or reaches the end. It is the simplest search algorithm and works on any list, sorted or unsorted.

Searching algorithms find a specific item within a collection of data. The two most fundamental approaches are linear search and binary search.

Bubble sort is a simple sorting algorithm that repeatedly swaps adjacent items that are in the wrong order. It is a great first algorithm to study because its logic is easy to follow step by step.

Insertion sort builds a sorted list one item at a time by inserting each new item into its correct position among the already-sorted items. It works especially well on small or nearly-sorted lists.

Selection sort finds the smallest item in the unsorted portion of a list and moves it into place, one item at a time. It is easy to understand and always makes the same number of comparisons.

Sorting algorithms arrange a list of items into a defined order. Understanding how they work helps you choose the right one for a given task.

Binary addition follows the same rules as normal addition, but only uses the digits 0 and 1.

Binary is a number system that uses only 0s and 1s. It is the language of computers because electronic circuits naturally represent two states: off and on.

A bit is the smallest unit of data in computing, and 8 bits make one byte.

Hexadecimal is a base-16 number system that computer scientists use as a shorthand for binary.

Compression reduces the size of files by encoding the data more efficiently. There are two main types: lossless compression, which preserves every bit of data, and lossy compression, which permanently removes some data to achieve smaller sizes.

Lossless compression reduces file size without losing any data, allowing the original file to be perfectly reconstructed.

Lossy compression reduces file size by permanently removing some data, achieving much smaller files at the cost of some quality.

Run-Length Encoding (RLE) is a simple lossless compression method that replaces consecutive repeated values with a count and a single value.

ASCII is a standard that assigns a unique number to each character so computers can store and share text.

All data in a computer is stored as binary, but different types of data — text, images, and sound — are encoded in very different ways.

Digital images are made up of tiny squares called pixels, each storing colour data as binary numbers.

The Caesar cipher is one of the oldest encryption methods, shifting each letter in a message by a fixed number of positions in the alphabet.

Encryption transforms readable data into an unreadable form so that only authorised parties can access it. It is the foundation of secure communication on the internet.

HTTPS uses encryption to protect data travelling between your browser and a website, keeping your passwords and personal information safe.

Symmetric encryption uses the same key to both encrypt and decrypt data, making it fast but requiring the key to be shared securely.

A file type (or file format) defines how data is organised and stored in a file. Different types are designed for different kinds of content, such as text, images, audio, and data tables.

Different image file formats use different methods to store pixel data, balancing quality, file size, and transparency support.

A text file stores data as plain characters using a character encoding like ASCII or UTF-8.

Study of how data is stored, represented, and processed in computers, including binary, compression, and encryption.

An algorithm is a step-by-step set of instructions for solving a problem or completing a task.

A bit is the smallest unit of data in computing, representing a single binary digit: either 0 or 1.

Key definitions and terms across computing topics for quick lookup and concept reinforcement.

A function is a named, reusable block of code that performs a specific task and can be called multiple times.

A variable is a named storage location in a program that holds a value which can change during execution.

An operating system (OS) is system software that manages computer hardware, software resources, and provides services for programs.

A Boolean expression is any expression that evaluates to either True or False. Understanding Boolean logic is essential for writing conditions and controlling program flow.

Conditionals allow a program to make decisions by running different blocks of code depending on whether a condition is true or false.

An if-else statement lets a program make decisions and follow different paths based on whether a condition is true or false. Decision-making is at the heart of every useful program.

Logical operators (and, or, not) combine Boolean expressions to create more powerful conditions. They are essential for writing programs that can handle complex real-world rules.

Every value in a program has a data type that determines what kind of information it holds and what operations can be performed on it.

A list stores multiple values in a single variable in a specific order. Lists are one of the most powerful data structures in Python and appear in almost every real program.

Strings store and manipulate text in programs. Python has a rich set of string operations that make it easy to process names, messages, and any other text data.

Type conversion changes a value from one data type to another. Python provides built-in functions to convert between integers, floats, strings, and Booleans.

Python comes with dozens of ready-made functions you can use immediately without writing any extra code. Knowing the most common ones saves time and makes your programs more readable.

Functions let you group a block of code under a name so you can reuse it anywhere in your program. They are the key to writing clean, organised, and maintainable code.

Parameters let functions accept input values, making them reusable for different situations. Understanding the difference between parameters and arguments is key to writing flexible code.

A return value is the result a function sends back to the code that called it. Return values let functions produce data that can be stored, printed, or used in further calculations.

Introduction to programming concepts and structures including variables, functions, loops, and conditionals.

A for loop repeats a block of code a known number of times, or once for each item in a collection. It is the most common type of loop in Python.

Loops let a program repeat a block of code multiple times without writing it out over and over. They are one of the most powerful tools in programming.

A nested loop is a loop placed inside another loop. They are used to work with grids, tables, and any situation that requires repeating a repetition.

A while loop repeats a block of code for as long as a condition remains true. It is perfect when you do not know in advance how many times you need to repeat.

Assignment stores a value in a variable. Expressions calculate new values using operators. Together they are the engine behind almost every program.

A constant is a named value that never changes while a program is running. Using constants makes code easier to read, maintain, and debug.

Scope determines which parts of a program can see and use a variable. Understanding scope prevents confusing bugs and helps you write cleaner code.

A variable is a named container that stores data in a program. Understanding variables is the first step to writing meaningful code.

The CPU (Central Processing Unit) is the main chip in a computer that carries out instructions and performs calculations.

Hardware refers to the physical components that make up a computer system. Understanding the main components and their roles is essential for studying how computers work.

RAM is the computer's short-term working memory, storing programs and data that are currently being used.

Storage devices permanently save programs and data even when the computer is switched off.

Study of computer hardware, networking, operating systems, and security principles.

The internet is a global network of computers that communicate using agreed protocols to share data and services.

An IP address is a unique numerical label assigned to every device on a network, allowing data to be sent to the right destination.

A computer network connects devices so they can communicate and share resources. Understanding networks is essential for grasping how the internet, cloud services, and everyday communication work.

Data packets are small chunks that large messages are broken into for transmission across a network, then reassembled at the destination.

File management is how an operating system organises, stores, names, and provides access to files on a storage device.

Multitasking allows an operating system to run multiple programs at the same time by rapidly switching the CPU between them.

An operating system is the core software that manages a computer's hardware and provides services for all other programs. Without it, no other software could run.

Malware is malicious software designed to damage, disrupt, or gain unauthorised access to computer systems.

A strong password is one of the most effective ways to protect your online accounts from unauthorised access.

Cybersecurity is the practice of protecting computer systems, networks, and data from unauthorised access, damage, or attack. Understanding common threats and defences is essential for every digital citizen.

Application software consists of programs designed to help users perform specific tasks, such as word processing, browsing, or gaming.

Software is the set of instructions that tells a computer what to do. It is divided into system software, which manages the hardware, and application software, which serves the user's needs.

System software manages the hardware and provides a platform for application software to run.