Programming

SDLC (Systems/Software Development Life Cycle)

A structured process followed to plan, create, test and deploy an information system, typically including analysis, design, development, testing, implementation and maintenance phases.

Systems analysis

The SDLC phase where the current system and its problems are investigated and the requirements for a new system are gathered and defined.

Systems design

The SDLC phase where the structure, interface, data and logic of the new system are planned before coding begins, e.g. via diagrams and prototypes.

Development/implementation phase (SDLC)

The SDLC phase where the actual system is built/coded based on the design specifications.

Testing phase (SDLC)

The SDLC phase where the system is checked for errors and verified against requirements before being released to users.

Maintenance phase (SDLC)

The ongoing SDLC phase after a system is deployed, involving bug fixes, updates and improvements over its lifetime.

Waterfall model

An SDLC model where each phase must be completed in a strict sequence before the next begins, with little revisiting of earlier phases.

Agile methodology

An SDLC approach that develops software through short, repeated cycles (sprints), allowing flexibility and continuous feedback throughout development.

Prototype

An early, simplified working model of a system or part of a system, built to test ideas and gather user feedback before full development.

Algorithm

A finite, step-by-step set of instructions designed to solve a specific problem or perform a specific task.

Pseudocode

A plain-language, structured way of describing an algorithm's logic without using the exact syntax of a specific programming language.

Flowchart

A diagram that uses standardised symbols to visually represent the sequence of steps and decisions in an algorithm.

Variable

A named location in memory used to store a value that can change while a program runs.

Constant

A named value in a program that is set once and does not change during program execution.

Data type (programming)

A classification specifying what kind of value a variable can hold, e.g. integer, string, boolean, float/real.

Sequence (control structure)

A control structure where program instructions are executed one after another, in the order they are written.

Selection (control structure)

A control structure that allows a program to choose between different paths of execution based on a condition, e.g. if-else statements.

Iteration (control structure)

A control structure that repeats a block of code multiple times, e.g. for loops and while loops, until a condition is met.

For loop

An iteration structure that repeats a block of code a specific, predetermined number of times.

While loop

An iteration structure that repeats a block of code as long as a specified condition remains true, checked before each repetition.

Repeat-until loop

An iteration structure that repeats a block of code until a specified condition becomes true, checked after each repetition (executes at least once).

Function/Procedure

A named, reusable block of code that performs a specific task and can be called from elsewhere in a program; a function typically returns a value.

Parameter

A variable listed in a function or procedure's definition that receives a value passed to it when the function/procedure is called.

Array

A data structure that stores a fixed-size, ordered collection of elements of the same data type, accessed via an index.

String

A data type used to store a sequence of characters, such as text or words.

Boolean

A data type that can only hold one of two values: true or false.

Object-oriented programming (OOP)

A programming paradigm based on organising code into "objects" that combine data (properties) and behaviour (methods), using concepts like classes, inheritance and encapsulation.

Class

A blueprint or template in OOP that defines the properties and methods that objects created from it will have.

Object (OOP)

A specific instance created from a class, with its own values for the class's properties.

Inheritance

An OOP concept where a new class (subclass) can inherit properties and methods from an existing class (superclass), promoting code reuse.

Encapsulation

An OOP concept where an object's internal data is hidden from outside access and can only be changed through defined methods, protecting data integrity.

Polymorphism

An OOP concept where a method can behave differently depending on the object calling it, even if the method name is the same.

Syntax error

An error that occurs when code does not follow the correct grammar/rules of the programming language, preventing it from compiling or running.

Logic error

An error where a program runs without crashing but produces incorrect results due to a flaw in the algorithm's logic.

Runtime error

An error that occurs while a program is executing, often caused by invalid operations such as dividing by zero or accessing invalid memory.

Debugging

The process of finding and fixing errors (bugs) in a program's code.

Compiler

A program that translates an entire program's source code into machine code (an executable file) before it is run.

Interpreter

A program that translates and executes source code line by line, without producing a separate executable file.

IDE (Integrated Development Environment)

Software that provides tools for writing, editing, testing and debugging code in one interface, e.g. Delphi, Visual Studio.

Comment (code)

Text within source code that is ignored by the compiler/interpreter, used by programmers to explain or document the code.