Portal:Computer programming

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Sample of a computer program (a minified version of the BootstrapJS library) on a screen

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...)

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Java is a high-level, general-purpose, memory-safe, object-oriented programming language. It is 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 usually 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 abilities (such as reflective programming (reflection) and runtime code modification) usually unavailable in traditional compiled languages.

Java gained popularity shortly after its release, and has been a popular programming language since then. Java was the third most popular programming language in 2022^[update] 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 designed 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 (VMs), and class libraries were 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, which bought Sun in 2010, offers its own HotSpot Java virtual machine. However, the official reference implementation is the OpenJDK JVM, which is open-source software used by most developers and is the default JVM for almost all Linux distributions. (Full article...)
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tcsh and sh shell windows on a Mac OS X Leopard desktop

A Unix shell is a shell that provides a command-line user interface for a Unix-like operating system. A Unix shell provides a command language that can be used either interactively or for writing a shell script.
A user typically works within a Unix shell via a terminal emulator; however, direct access via serial hardware connections or a Secure Shell are common for server systems. Although use of a Unix shell is popular with some users, others prefer to use a graphical shell in a windowing system, such as those provided in desktop Linux distributions or macOS, instead of a command-line interface (CLI).

A user may have access to multiple Unix shells with one configured to run by default when the user logs in interactively. The default selection is typically stored in a user's profile (for example, in the local passwd file or in a distributed configuration system such as NIS or LDAP). A user may use other shells nested inside the default shell.

A Unix shell may provide many features including: variable definition and substitution, command substitution, filename wildcarding, stream piping, control flow structures (condition-testing and iteration), working directory context, and here document. (Full article...)
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In the C++ programming language, decltype (for "declared type") is a specifier keyword used to query the type of an expression. Introduced in C++11, its primary intended use is in generic programming, where it is often difficult, or even impossible, to express types that depend on template parameters.

As generic programming techniques became increasingly popular throughout the 1990s, the need for a type-deduction mechanism was recognized. Many compiler vendors implemented their own versions of the operator, typically called typeof, and some portable implementations with limited functionality, based on existing language features were developed. In 2002, Bjarne Stroustrup proposed that a standardized version of the operator be added to the C++ language, and suggested the name "decltype", to reflect that the operator would yield the "declared type" of an expression.

decltype's semantics were designed to cater to both generic library writers and novice programmers. In general, the deduced type matches the type of the object or function exactly as declared in the source code. Like the sizeof operator, decltype's operand is not evaluated. (Full article...)
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Rust is a general-purpose programming language which emphasizes performance, type safety, concurrency, and memory safety.

Rust supports multiple programming paradigms. It was influenced by ideas from functional programming, including immutability, higher-order functions, algebraic data types, and pattern matching. It also supports object-oriented programming via structs, enums, traits, and methods. Rust enforces memory safety (i.e., that all references point to valid memory) without a conventional garbage collector; instead, memory safety errors and data races are prevented by the "borrow checker", which tracks the object lifetime of references at compile time.

Software developer Graydon Hoare created Rust in 2006 while working at Mozilla, which officially sponsored the project in 2009. The first stable release, Rust 1.0, was published in May 2015. The project has been sponsored by the Rust Foundation since February 2021. (Full article...)
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Block diagram of a basic computer with uniprocessor CPU. Black lines indicate the flow of control signals, whereas red lines indicate the flow of processor instructions and data. Arrows indicate the direction of flow.

In computer science and computer engineering, a computer architecture is the conceptual design and operational structure of a computer system that define how component parts are organized and interact to execute programs efficiently. It is often a general description that ignores precise implementation details. It covers the instruction set architecture, CPU microarchitecture, memory, and input/output systems.

Computer architecture also considers tradeoffs between performance, cost, power, reliability, and security. (Full article...)
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Logo endorsed by the C++ standards committee

C++ is a high-level, general-purpose programming language created by Danish computer scientist Bjarne Stroustrup. First released in 1985 as an extension of the C programming language, adding object-oriented (OOP) features, it has since expanded significantly over time adding more OOP and other features; as of 1997^[update]/C++98 standardization, C++ has added functional features, in addition to facilities for low-level memory manipulation for systems like microcomputers or to make operating systems like Linux or Windows, and even later came features like generic programming (through the use of templates). C++ is usually implemented as a compiled language, and many vendors provide C++ compilers, including the Free Software Foundation, LLVM, Microsoft, Intel, Embarcadero, Oracle, and IBM.

C++ was designed with systems programming and embedded, resource-constrained software and large systems in mind, with performance, efficiency, and flexibility of use as its design highlights. C++ has also been found useful in many other contexts, with key strengths being software infrastructure and resource-constrained applications, including desktop applications, video games, servers (e.g., e-commerce, web search, or databases), and performance-critical applications (e.g., telephone switches or space probes).

C++ is standardized by the International Organization for Standardization (ISO), with the latest standard version ratified and published by ISO in October 2024 as ISO/IEC 14882:2024 (informally known as C++23). The C++ programming language was initially standardized in 1998 as ISO/IEC 14882:1998, which was then amended by the C++03, C++11, C++14, C++17, and C++20 standards. The next C++23 standard superseded these with new features and an enlarged standard library. Before the initial standardization in 1998, C++ was developed by Stroustrup at Bell Labs since 1979 as an extension of the C language; he wanted an efficient and flexible language similar to C that also provided high-level features for program organization. Since 2012, C++ has been on a three-year release schedule with C++29 as the next planned standard. (Full article...)
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Object Pascal is an extension to the programming language Pascal that provides object-oriented programming (OOP) features such as classes and methods.

The language was originally developed by Apple Computer as Clascal for the Lisa Workshop development system. As Lisa gave way to Macintosh, Apple collaborated with Niklaus Wirth, the author of Pascal, to develop an officially standardized version of Clascal. This was renamed Object Pascal. Through the mid-1980s, Object Pascal was the main programming language for early versions of the MacApp application framework. The language lost its place as the main development language on the Mac in 1991 with the release of the C++-based MacApp 3.0. Official support ended in 1996.

Symantec also developed a compiler for Object Pascal for their Think Pascal product, which could compile programs much faster than Apple's own Macintosh Programmer's Workshop (MPW). Symantec then developed the Think Class Library (TCL), based on MacApp concepts, which could be called from both Object Pascal and THINK C. The Think suite largely displaced MPW as the main development platform on the Mac in the late 1980s. (Full article...)
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A computer lab contains a wide range of information technology elements, including hardware, software and storage systems.

Information technology (IT) is the study or use of computers, telecommunication systems and other devices to create, process, store, retrieve and transmit information. While the term is commonly used to refer to computers and computer networks, it also encompasses other information distribution technologies such as television and telephones. Information technology is an application of computer science and computer engineering.

An information technology system (IT system) is generally an information system, a communications system, or, more specifically speaking, a computer system — including all hardware, software, and peripheral equipment — operated by a limited group of IT users, and an IT project usually refers to the commissioning and implementation of an IT system. IT systems play a vital role in facilitating efficient data management, enhancing communication networks, and supporting organizational processes across various industries. Successful IT projects require meticulous planning and ongoing maintenance to ensure optimal functionality and alignment with organizational objectives.

Although humans have been storing, retrieving, manipulating, analysing and communicating information since the earliest writing systems were developed, the term information technology in its modern sense first appeared in a 1958 article published in the Harvard Business Review; authors Harold J. Leavitt and Thomas L. Whisler commented that "the new technology does not yet have a single established name. We shall call it information technology (IT)." Their definition consists of three categories: techniques for processing, the application of statistical and mathematical methods to decision-making, and the simulation of higher-order thinking through computer programs. (Full article...)
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Torvalds at the LinuxCon Europe 2014

Linus Benedict Torvalds (born 28 December 1969) is a Finnish and American software engineer who is the creator and lead developer of the Linux kernel since 1991. He also created the distributed version control system Git.

Torvalds was one of the recipients of the 2012 Millennium Technology Prize "in recognition of his creation of a new open source operating system for computers leading to the widely used Linux kernel". He is also the recipient of the 2014 IEEE Computer Society Computer Pioneer Award and the 2018 IEEE Masaru Ibuka Consumer Electronics Award. (Full article...)
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Forth is a 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. (Full article...)
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Structured Query Language (SQL) (pronounced /ˌɛsˌkjuˈɛl/ S-Q-L; or alternatively as /ˈsiːkwəl/ "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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The Greek lowercase omega (ω) character is used to represent Null in database theory.

In the SQL database query language, null or NULL is a special marker used to indicate that a data value does not exist in the database. Introduced by the creator of the relational database model, E. F. Codd, SQL null serves to fulfill the requirement that all true relational database management systems (RDBMS) support a representation of "missing information and inapplicable information". Codd also introduced the use of the lowercase Greek omega (ω) symbol to represent null in database theory. In SQL, NULL is a reserved word used to identify this marker.

A null should not be confused with a value of 0. A null indicates a lack of a value, which is not the same as a zero value. For example, in the question "How many books does Adam own?", the answer may be "zero" (the number of books is known to be zero) or "null" (the number of books is not known). In a database table, the column reporting this answer would start with no value (marked by null), and it would not be updated with the value zero until it is ascertained that Adam owns no books.

In SQL, null is a marker, not a value. This usage differs from most programming languages, where a null value of a reference means it is not pointing to any object. (Full article...)
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Source code for a computer program written in the JavaScript language. It demonstrates the appendChild method. The method adds a new child node to an existing parent node. It is commonly used to dynamically modify the structure of an HTML document.

A computer program is a sequence or set of instructions in a programming language for a computer to execute. It is one component of software, which also includes documentation and other intangible components.

A computer program in its human-readable form is called source code. Source code needs another computer program to execute because computers can only execute their native machine instructions. Therefore, source code may be translated to machine instructions using a compiler written for the language. (Assembly language programs are translated using an assembler.) The resulting file is called an executable. Alternatively, source code may execute within an interpreter written for the language.

If the executable is requested for execution, then the operating system loads it into memory and starts a process. The central processing unit will soon switch to this process so it can fetch, decode, and then execute each machine instruction. (Full article...)
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In computing, a compiler is software that translates computer code written in one programming language (the source language) into another language (the target language). The name "compiler" is primarily used for programs that translate source code from a high-level programming language to a low-level programming language (e.g., assembly language, object code, or machine code) to create an executable program.

There are many different types of compilers which produce output in different useful forms. A cross-compiler produces code for a different central processing unit (CPU) or operating system than the one on which the cross-compiler itself runs. A bootstrap compiler is often a temporary compiler, used for compiling a more permanent or better optimized compiler for a language.

Related software include decompilers, programs that translate from low-level languages to higher-level ones; programs that translate between high-level languages, usually called source-to-source compilers or transpilers; language rewriters, usually programs that translate the form of expressions without a change of language; and compiler-compilers, compilers that produce compilers (or parts of them), often in a generic and reusable way so as to be able to produce many differing compilers. (Full article...)
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Laboratory Virtual Instrument Engineering Workbench (LabVIEW) is a graphical system design and development platform produced and distributed by National Instruments, based on a programming environment that uses a visual programming language. It is widely used for data acquisition, instrument control, and industrial automation. It provides tools for designing and deploying complex test and measurement systems.

The visual (aka graphical) programming language is called "G" (not to be confused with G-code). It is a dataflow language originally developed by National Instruments. LabVIEW is supported on a variety of operating systems (OSs), including macOS and other versions of Unix and Linux, as well as Microsoft Windows.

The latest versions of LabVIEW are LabVIEW 2024 Q3 (released in July 2024) and LabVIEW NXG 5.1 (released in January 2021). National Instruments released the free for non-commercial use LabVIEW and LabVIEW NXG Community editions on April 28, 2020. (Full article...)

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Image 1GNOME Shell, GNOME Clocks, Evince, gThumb and GNOME Files at version 3.30, in a dark theme
Image 2Output 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.
Image 3Stephen Wolfram is a British-American computer scientist, physicist, and businessman. He is known for his work in computer science, mathematics, and in theoretical physics.
Image 4Grace 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).
Image 5A head crash on a modern hard disk drive
Image 6Deep 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.
Image 7Margaret Hamilton standing next to the navigation software that she and her MIT team produced for the Apollo Project.
Image 8An IBM Port-A-Punch punched card
Image 9Partial view of the Mandelbrot set. Step 1 of a zoom sequence: Gap between the "head" and the "body" also called the "seahorse valley".
Image 10Partial 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.
Image 11A view of the GNU nano Text editor version 6.0
Image 12Ada 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.
Image 13A screenshot of GNU Emacs 22.0.91.1, from Ubuntu’s emacs-snapshot-gtk package.
Image 14An animation of the quicksort algorithm sorting an array of randomized values
Image 15This image (when viewed in full size, 1000 pixels wide) contains 1 million pixels, each of a different color.
Image 16A lone house. An image made using Blender 3D.
Image 17Animation of a Non-uniform rational B-spline surface. Modeled and rendered in Cobalt.
Image 18Bill Gosper's Glider Gun in action

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28 July 2026 –: Taiwanese prosecutors detain an Nvidia employee in an investigation into alleged smuggling of advanced artificial intelligence chips to China through falsified transport documents. Authorities hold seven people over shipments of about 50 Supermicro servers that may violate U.S. export controls. (AFP via France 24)

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