Portal:Computer programming
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The Computer Programming Portal
Computer programming or coding is the composition of sequences of instructions, called programs, that computers can follow to perform tasks. It involves designing and implementing algorithms, step-by-step specifications of procedures, by writing code in one or more programming languages. Programmers typically use high-level programming languages that are more easily intelligible to humans than machine code, which is directly executed by the central processing unit. Proficient programming usually requires expertise in several different subjects, including knowledge of the application domain, details of programming languages and generic code libraries, specialized algorithms, and formal logic.
Auxiliary tasks accompanying and related to programming include analyzing requirements, testing, debugging (investigating and fixing problems), implementation of build systems, and management of derived artifacts, such as programs' machine code. While these are sometimes considered programming, often the term software development is used for this larger overall process – with the terms programming, implementation, and coding reserved for the writing and editing of code per se. Sometimes software development is known as software engineering, especially when it employs formal methods or follows an engineering design process. (Full article...)
Selected articles - load new batch
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Image 1Structured Query Language (SQL) (pronounced S-Q-L; historically "sequel") is a domain-specific language used to manage data, especially in a relational database management system (RDBMS). It is particularly useful in handling structured data, i.e., data incorporating relations among entities and variables.
Introduced in the 1970s, SQL offered two main advantages over older read–write APIs such as ISAM or VSAM. Firstly, it introduced the concept of accessing many records with one single command. Secondly, it eliminates the need to specify how to reach a record, i.e., with or without an index.
Originally based upon relational algebra and tuple relational calculus, SQL consists of many types of statements, which may be informally classed as sublanguages, commonly: Data query Language (DQL), Data Definition Language (DDL), Data Control Language (DCL), and Data Manipulation Language (DML). (Full article...) -
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F# (pronounced F sharp) is a general-purpose, high-level, strongly typed, multi-paradigm programming language that encompasses functional, imperative, and object-oriented programming methods. It is most often used as a cross-platform Common Language Infrastructure (CLI) language on .NET, but can also generate JavaScript and graphics processing unit (GPU) code.
F# is developed by the F# Software Foundation, Microsoft and open contributors. An open source, cross-platform compiler for F# is available from the F# Software Foundation. F# is a fully supported language in Visual Studio and JetBrains Rider. Plug-ins supporting F# exist for many widely used editors including Visual Studio Code, Vim, and Emacs.
F# is a member of the ML language family and originated as a .NET Framework implementation of a core of the programming language OCaml. It has also been influenced by C#,
Python, Haskell, Scala and Erlang. (Full article...) -
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Parallel computing is a type of computation in which many calculations or processes are carried out simultaneously. Large problems can often be divided into smaller ones, which can then be solved at the same time. There are several different forms of parallel computing: bit-level, instruction-level, data, and task parallelism. Parallelism has long been employed in high-performance computing, but has gained broader interest due to the physical constraints preventing frequency scaling. As power consumption (and consequently heat generation) by computers has become a concern in recent years, parallel computing has become the dominant paradigm in computer architecture, mainly in the form of multi-core processors.
Parallel computing is closely related to concurrent computing—they are frequently used together, and often conflated, though the two are distinct: it is possible to have parallelism without concurrency, and concurrency without parallelism (such as multitasking by time-sharing on a single-core CPU). In parallel computing, a computational task is typically broken down into several, often many, very similar sub-tasks that can be processed independently and whose results are combined afterwards, upon completion. In contrast, in concurrent computing, the various processes often do not address related tasks; when they do, as is typical in distributed computing, the separate tasks may have a varied nature and often require some inter-process communication during execution.
Parallel computers can be roughly classified according to the level at which the hardware supports parallelism, with multi-core and multi-processor computers having multiple processing elements within a single machine, while clusters, MPPs, and grids use multiple computers to work on the same task. Specialized parallel computer architectures are sometimes used alongside traditional processors, for accelerating specific tasks. (Full article...) -
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A Unix shell is a command-line interpreter or shell that provides a command line user interface for Unix-like operating systems. The shell is both an interactive command language and a scripting language, and is used by the operating system to control the execution of the system using shell scripts.
Users typically interact with a Unix shell using a terminal emulator; however, direct operation via serial hardware connections or Secure Shell are common for server systems. All Unix shells provide filename wildcarding, piping, here documents, command substitution, variables and control structures for condition-testing and iteration. (Full article...) -
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C (pronounced /ˈsiː/ – like the letter c) is a general-purpose computer programming language. It was created in the 1970s by Dennis Ritchie, and remains very widely used and influential. By design, C's features cleanly reflect the capabilities of the targeted CPUs. It has found lasting use in operating systems, device drivers, and protocol stacks, but its use in application software has been decreasing. C is commonly used on computer architectures that range from the largest supercomputers to the smallest microcontrollers and embedded systems.
A successor to the programming language B, C was originally developed at Bell Labs by Ritchie between 1972 and 1973 to construct utilities running on Unix. It was applied to re-implementing the kernel of the Unix operating system. During the 1980s, C gradually gained popularity. It has become one of the most widely used programming languages, with C compilers available for practically all modern computer architectures and operating systems. The book The C Programming Language, co-authored by the original language designer, served for many years as the de facto standard for the language. C has been standardized since 1989 by the American National Standards Institute (ANSI) and the International Organization for Standardization (ISO).
C is an imperative procedural language, supporting structured programming, lexical variable scope, and recursion, with a static type system. It was designed to be compiled to provide low-level access to memory and language constructs that map efficiently to machine instructions, all with minimal runtime support. Despite its low-level capabilities, the language was designed to encourage cross-platform programming. A standards-compliant C program written with portability in mind can be compiled for a wide variety of computer platforms and operating systems with few changes to its source code. (Full article...) -
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JavaScript (/ˈdʒɑːvəskrɪpt/), often abbreviated as JS, is a programming language and core technology of the Web, alongside HTML and CSS. 99% of websites use JavaScript on the client side for webpage behavior.
Web browsers have a dedicated JavaScript engine that executes the client code. These engines are also utilized in some servers and a variety of apps. The most popular runtime system for non-browser usage is Node.js.
JavaScript is a high-level, often just-in-time compiled language that conforms to the ECMAScript standard. It has dynamic typing, prototype-based object-orientation, and first-class functions. It is multi-paradigm, supporting event-driven, functional, and imperative programming styles. It has application programming interfaces (APIs) for working with text, dates, regular expressions, standard data structures, and the Document Object Model (DOM). (Full article...) -
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Rust is a multi-paradigm, general-purpose programming language that emphasizes performance, type safety, and concurrency. It enforces memory safety—meaning that all references point to valid memory—without a garbage collector. To simultaneously enforce memory safety and prevent data races, its "borrow checker" tracks the object lifetime of all references in a program during compilation.
Rust was influenced by ideas from functional programming, including immutability, higher-order functions, and algebraic data types. It is popular for systems programming.
Software developer Graydon Hoare created Rust as a personal project while working at Mozilla Research in 2006. Mozilla officially sponsored the project in 2009. In the years following the first stable release in May 2015, Rust was adopted by companies including Amazon, Discord, Dropbox, Google (Alphabet), Meta, and Microsoft. In December 2022, it became the first language other than C and assembly to be supported in the development of the Linux kernel. (Full article...) -
Image 8Go is a statically typed, compiled high-level programming language designed at Google by Robert Griesemer, Rob Pike, and Ken Thompson. It is syntactically similar to C, but also has memory safety, garbage collection, structural typing, and CSP-style concurrency. It is often referred to as Golang because of its former domain name,
golang.org
, but its proper name is Go.
There are two major implementations:- Google's self-hosting "gc" compiler toolchain, targeting multiple operating systems and WebAssembly.
- gofrontend, a frontend to other compilers, with the libgo library. With GCC the combination is gccgo; with LLVM the combination is gollvm.
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The analytical engine was a proposed digital mechanical general-purpose computer designed by English mathematician and computer pioneer Charles Babbage. It was first described in 1837 as the successor to Babbage's difference engine, which was a design for a simpler mechanical calculator.
The analytical engine incorporated an arithmetic logic unit, control flow in the form of conditional branching and loops, and integrated memory, making it the first design for a general-purpose computer that could be described in modern terms as Turing-complete. In other words, the structure of the analytical engine was essentially the same as that which has dominated computer design in the electronic era. The analytical engine is one of the most successful achievements of Charles Babbage.
Babbage was never able to complete construction of any of his machines due to conflicts with his chief engineer and inadequate funding. It was not until 1941 that Konrad Zuse built the first general-purpose computer, Z3, more than a century after Babbage had proposed the pioneering analytical engine in 1837. (Full article...) -
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Andrew Stuart Tanenbaum (born March 16, 1944), sometimes referred to by the handle ast, is an American–Dutch computer scientist and professor emeritus of computer science at the Vrije Universiteit Amsterdam in the Netherlands.
He is the author of MINIX, a free Unix-like operating system for teaching purposes, and has written multiple computer science textbooks regarded as standard texts in the field. He regards his teaching job as his most important work. Since 2004 he has operated Electoral-vote.com, a website dedicated to analysis of polling data in federal elections in the United States. (Full article...) -
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Computer graphics deals with generating images and art with the aid of computers. Today, computer graphics is a core technology in digital photography, film, video games, digital art, cell phone and computer displays, and many specialized applications. A great deal of specialized hardware and software has been developed, with the displays of most devices being driven by computer graphics hardware. It is a vast and recently developed area of computer science. The phrase was coined in 1960 by computer graphics researchers Verne Hudson and William Fetter of Boeing. It is often abbreviated as CG, or typically in the context of film as computer generated imagery (CGI). The non-artistic aspects of computer graphics are the subject of computer science research.
Some topics in computer graphics include user interface design, sprite graphics, rendering, ray tracing, geometry processing, computer animation, vector graphics, 3D modeling, shaders, GPU design, implicit surfaces, visualization, scientific computing, image processing, computational photography, scientific visualization, computational geometry and computer vision, among others. The overall methodology depends heavily on the underlying sciences of geometry, optics, physics, and perception.
Computer graphics is responsible for displaying art and image data effectively and meaningfully to the consumer. It is also used for processing image data received from the physical world, such as photo and video content. Computer graphics development has had a significant impact on many types of media and has revolutionized animation, movies, advertising, and video games, in general. (Full article...) -
Image 12In C++ computer programming, allocators are a component of the C++ Standard Library. The standard library provides several data structures, such as list and set, commonly referred to as containers. A common trait among these containers is their ability to change size during the execution of the program. To achieve this, some form of dynamic memory allocation is usually required. Allocators handle all the requests for allocation and deallocation of memory for a given container. The C++ Standard Library provides general-purpose allocators that are used by default, however, custom allocators may also be supplied by the programmer.
Allocators were invented by Alexander Stepanov as part of the Standard Template Library (STL). They were originally intended as a means to make the library more flexible and independent of the underlying memory model, allowing programmers to utilize custom pointer and reference types with the library. However, in the process of adopting STL into the C++ standard, the C++ standardization committee realized that a complete abstraction of the memory model would incur unacceptable performance penalties. To remedy this, the requirements of allocators were made more restrictive. As a result, the level of customization provided by allocators is more limited than was originally envisioned by Stepanov.
Nevertheless, there are many scenarios where customized allocators are desirable. Some of the most common reasons for writing custom allocators include improving performance of allocations by using memory pools, and encapsulating access to different types of memory, like shared memory or garbage-collected memory. In particular, programs with many frequent allocations of small amounts of memory may benefit greatly from specialized allocators, both in terms of running time and memory footprint. (Full article...) -
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R is a programming language for statistical computing and data visualization. It has been adopted in the fields of data mining, bioinformatics, and data analysis.
The core R language is augmented by a large number of extension packages, containing reusable code, documentation, and sample data.
R software is open-source and free software. It is licensed by the GNU Project and available under the GNU General Public License. It is written primarily in C, Fortran, and R itself. Precompiled executables are provided for various operating systems. (Full article...) -
Image 14Forth is a procedural, concatenative, stack-oriented programming language and interactive integrated development environment designed by Charles H. "Chuck" Moore and first used by other programmers in 1970. Although not an acronym, the language's name in its early years was often spelled in all capital letters as FORTH. The FORTH-79 and FORTH-83 implementations, which were not written by Moore, became de facto standards, and an official technical standard of the language was published in 1994 as ANS Forth. A wide range of Forth derivatives existed before and after ANS Forth. The free and open-source software Gforth implementation is actively maintained, as are several commercially supported systems.
Forth typically combines a compiler with an integrated command shell, where the user interacts via subroutines called words. Words can be defined, tested, redefined, and debugged without recompiling or restarting the whole program. All syntactic elements, including variables, operators, and control flow, are defined as words. A stack is used to pass parameters between words, leading to a Reverse Polish Notation style.
For much of Forth's existence, the standard technique was to compile to threaded code, which can be interpreted faster than bytecode. One of the early benefits of Forth was size: an entire development environment—including compiler, editor, and user programs—could fit in memory on an 8-bit or similarly limited system. No longer constrained by space, there are modern implementations that generate optimized machine code like other language compilers. The relative simplicity of creating a basic Forth system has led to many personal and proprietary variants, such as the custom Forth used to implement the bestselling 1986 video game Starflight from Electronic Arts. (Full article...) -
Image 15Java is a high-level, class-based, object-oriented programming language that is designed to have as few implementation dependencies as possible. It is a general-purpose programming language intended to let programmers write once, run anywhere (WORA), meaning that compiled Java code can run on all platforms that support Java without the need to recompile. Java applications are typically compiled to bytecode that can run on any Java virtual machine (JVM) regardless of the underlying computer architecture. The syntax of Java is similar to C and C++, but has fewer low-level facilities than either of them. The Java runtime provides dynamic capabilities (such as reflection and runtime code modification) that are typically not available in traditional compiled languages.
Java gained popularity shortly after its release, and has been a very popular programming language since then. Java was the third most popular programming language in according to GitHub. Although still widely popular, there has been a gradual decline in use of Java in recent years with other languages using JVM gaining popularity.
Java was originally developed by James Gosling at Sun Microsystems. It was released in May 1995 as a core component of Sun's Java platform. The original and reference implementation Java compilers, virtual machines, and class libraries were originally released by Sun under proprietary licenses. As of May 2007, in compliance with the specifications of the Java Community Process, Sun had relicensed most of its Java technologies under the GPL-2.0-only license. Oracle offers its own HotSpot Java Virtual Machine, however the official reference implementation is the OpenJDK JVM which is free open-source software and used by most developers and is the default JVM for almost all Linux distributions. (Full article...)
Selected images
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Image 1A head crash on a modern hard disk drive
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Image 2Margaret Hamilton standing next to the navigation software that she and her MIT team produced for the Apollo Project.
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Image 3A lone house. An image made using Blender 3D.
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Image 4Deep Blue was a chess-playing expert system run on a unique purpose-built IBM supercomputer. It was the first computer to win a game, and the first to win a match, against a reigning world champion under regular time controls. Photo taken at the Computer History Museum.
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Image 6Grace Hopper at the UNIVAC keyboard, c. 1960. Grace Brewster Murray: American mathematician and rear admiral in the U.S. Navy who was a pioneer in developing computer technology, helping to devise UNIVAC I. the first commercial electronic computer, and naval applications for COBOL (common-business-oriented language).
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Image 7Partial map of the Internet based on the January 15, 2005 data found on opte.org. Each line is drawn between two nodes, representing two IP addresses. The length of the lines are indicative of the delay between those two nodes. This graph represents less than 30% of the Class C networks reachable by the data collection program in early 2005.
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Image 8Stephen Wolfram is a British-American computer scientist, physicist, and businessman. He is known for his work in computer science, mathematics, and in theoretical physics.
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Image 9A view of the GNU nano Text editor version 6.0
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Image 10Partial view of the Mandelbrot set. Step 1 of a zoom sequence: Gap between the "head" and the "body" also called the "seahorse valley".
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Image 11Ada Lovelace was an English mathematician and writer, chiefly known for her work on Charles Babbage's proposed mechanical general-purpose computer, the Analytical Engine. She was the first to recognize that the machine had applications beyond pure calculation, and to have published the first algorithm intended to be carried out by such a machine. As a result, she is often regarded as the first computer programmer.
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Image 12Output from a (linearised) shallow water equation model of water in a bathtub. The water experiences 5 splashes which generate surface gravity waves that propagate away from the splash locations and reflect off of the bathtub walls.
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Image 13GNOME Shell, GNOME Clocks, Evince, gThumb and GNOME Files at version 3.30, in a dark theme
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Image 15This image (when viewed in full size, 1000 pixels wide) contains 1 million pixels, each of a different color.
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Image 16An IBM Port-A-Punch punched card
Did you know? - load more entries
- ... that the Gale–Shapley algorithm was used to assign medical students to residencies long before its publication by Gale and Shapley?
- ... that Brazilian computer science researcher and internet pioneer Tadao Takahashi negotiated with drug lords to install internet equipment in his country?
- ... that Guy Parmelin, now President of Switzerland, opened the study program of cyber security of the Lucerne School of Information Technology in 2018?
- ... that the first official result for the TPC-C benchmark in 1992 was 54, and now stands at 707 million?
- ... that Phil Fletcher as Hacker T. Dog caused Lauren Layfield to make the "most famous snort" in the United Kingdom in 2016?
- ... that the programming language Acorn System BASIC was so non-standard that one commenter suggested that using it on the BBC Micro would be a disaster?
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