Programming paradigm in the context of Side effect (computer science)

Logic programming is a programming, database and knowledge representation paradigm based on formal logic. A logic program is a set of sentences in logical form, representing knowledge about some problem domain. Computation is performed by applying logical reasoning to that knowledge, to solve problems in the domain. Major logic programming language families include Prolog, Answer Set Programming (ASP) and Datalog. In all of these languages, rules are written in the form of clauses:

and are read as declarative sentences in logical form:

In computer science, functional programming is a programming paradigm where programs are constructed by applying and composing functions. It is a declarative programming paradigm in which function definitions are trees of expressions that map values to other values, rather than a sequence of imperative statements which update the running state of the program.

In functional programming, functions are treated as first-class citizens, meaning that they can be bound to names (including local identifiers), passed as arguments, and returned from other functions, just as any other data type can. This allows programs to be written in a declarative and composable style, where small functions are combined in a modular manner.

Procedural programming is a programming paradigm, classified as imperative programming, that involves implementing the behavior of a computer program as procedures (a.k.a. functions, subroutines) that call each other. The resulting program is a series of steps that forms a hierarchy of calls to its constituent procedures.

The first major procedural programming languages appeared c. 1957–1964, including Fortran, ALGOL, COBOL, PL/I and BASIC. Pascal and C were published c. 1970–1972.

Object-oriented programming (OOP) is a programming paradigm based on the object – a software entity that encapsulates data and function(s). An OOP computer program consists of objects that interact with one another. A programming language that provides OOP features is classified as an OOP language but as the set of features that contribute to OOP is contended, classifying a language as OOP and the degree to which it supports or is OOP, are debatable. As paradigms are not mutually exclusive, a language can be multi-paradigm; can be categorized as more than only OOP.

Sometimes, objects represent real-world things and processes in digital form. For example, a graphics program may have objects such as circle, square, and menu. An online shopping system might have objects such as shopping cart, customer, and product. Niklaus Wirth said, "This paradigm [OOP] closely reflects the structure of systems in the real world and is therefore well suited to model complex systems with complex behavior".

Modular programming is a programming paradigm that emphasizes organizing the functions of a codebase into independent modules – each providing an aspect of a computer program in its entirety without providing other aspects.

A module interface expresses the elements that are provided and required by the module. The elements defined in the interface are detectable by other modules. The implementation contains the working code that corresponds to the elements declared in the interface.

In software, control flow (or flow of control) describes how execution progresses from one command to the next. In many contexts, such as machine code and an imperative programming language, control progresses sequentially (to the command located immediately after the currently executing command) except when a command transfers control to another point – in which case the command is classified as a control flow command. Depending on context, other terms are used instead of command. For example, in machine code, the typical term is instruction and in an imperative language, the typical term is statement.

Although an imperative language encodes control flow explicitly, languages of other programming paradigms are less focused on control flow. A declarative language specifies desired results without prescribing an order of operations. A functional language uses both language constructs and functions to control flow even though they are usually not called control flow statements.

Python is a high-level, general-purpose programming language. Its design philosophy emphasizes code readability with the use of significant indentation. Python is dynamically type-checked and garbage-collected. It supports multiple programming paradigms, including structured (particularly procedural), object-oriented and functional programming.

Guido van Rossum began working on Python in the late 1980s as a successor to the ABC programming language. Python 3.0, released in 2008, was a major revision and not completely backward-compatible with earlier versions. Beginning with Python 3.5, capabilities and keywords for typing were added to the language, allowing optional static typing. As of 2025, the Python Software Foundation supports Python 3.10, 3.11, 3.12, 3.13, and 3.14, following the projects annual release cycle and five-year support policy. Earlier versions in the 3.x series have reached end-of-life and no longer receive security updates.

In computer science, cloning refers to the making of an exact copy of an object, frequently under the paradigm of instance-based programming, or object-oriented programming (OOP).

Object-oriented programming (OOP) is a programming paradigm based on objects – software entities that encapsulate data and function(s). An OOP computer program consists of objects that interact with one another. An OOP language is one that provides object-oriented programming features, but as the set of features that contribute to OOP is contested, classifying a language as OOP – and the degree to which it supports OOP – is debatable. As paradigms are not mutually exclusive, a language can be multi-paradigm (i.e. categorized as more than only OOP).

Notable languages with OOP support include Ada, ActionScript, C++, Common Lisp, C#, Dart, Eiffel, Fortran 2003, Haxe, Java, JavaScript, Kotlin, Logo, MATLAB, Objective-C, Object Pascal, Perl, PHP, Python, R, Raku, Ruby, Scala, SIMSCRIPT, Simula, Smalltalk, Swift, Vala and Visual Basic (.NET).

In computer science, declarative programming is a programming paradigm that expresses the logic of a computation without describing its control flow.

Many languages that apply this style attempt to minimize or eliminate side effects by describing what the program must accomplish in terms of the problem domain, rather than describing how to accomplish it as a sequence of the programming language primitives (the how being left up to the language's implementation). This is in contrast with imperative programming, which implements algorithms in explicit steps.

In computer science, imperative programming is a programming paradigm of software that uses statements that change a process' state. In much the same way that the imperative mood in natural languages expresses commands, an imperative program consists of commands for the computer to perform. Imperative programming focuses on describing how a program operates step by step (with general order of the steps being determined in source code by the placement of statements one below the other), rather than on high-level descriptions of its expected results.

The term is often used in contrast to declarative programming, which focuses on what the program should accomplish without specifying all the details of how the program should achieve the result.

Structured programming is a programming paradigm characterized by source code that uses block-based source code structure to encode control flow such as sequence, selection (i.e. if-then-else and switch) and iteration (i.e. for and while).

Originally, the central goal of the structured programming movement was to eliminate the need for and use of the goto statement. As goto provides powerful and flexible flow control, it can be used to write any arbitrarily complex algorithm, but the resulting code often has significant quality issues, commonly described as spaghetti code. Structured programming replaces goto with constructs that tend to result in better code. The paradigm became popular and for the most part achieved the goal of supplanting goto. In fact, its ubiquity is so thorough that for much of software development, it is simply the way code is written, no longer a topic of discussion as it once was.

Programming languages can be grouped by the number and types of paradigms supported.

In computer science, functional programming is a programming paradigm where programs are constructed by applying and composing functions. It is a declarative programming paradigm in which function definitions are trees of expressions that map values to other values, rather than a sequence of imperative statements which update the running state of the program.

In functional programming, functions are treated as first-class entities, meaning that they can be bound to names (including local identifiers), passed as arguments, and returned from other functions, just as any other data type can. This allows programs to be written in a declarative and composable style, where small functions are combined in a modular manner.