Portal:Computer programming

MATLAB (Matrix Laboratory) is a proprietary multi-paradigm programming language and numeric computing environment developed by MathWorks. MATLAB allows matrix manipulations, plotting of functions and data, implementation of algorithms, creation of user interfaces, and interfacing with programs written in other languages.

Although MATLAB is intended primarily for numeric computing, an optional toolbox uses the MuPAD symbolic engine allowing access to symbolic computing abilities. An additional package, Simulink, adds graphical multi-domain simulation and model-based design for dynamic and embedded systems.
As of 2020^[update], MATLAB has more than four million users worldwide. They come from various backgrounds of engineering, science, and economics. As of 2017^[update], more than 5000 global colleges and universities use MATLAB to support instruction and research. (Full article...)

In 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...)

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...)

Kotlin (/ˈkɒtlɪn/) is a cross-platform, statically typed, general-purpose high-level programming language with type inference. Kotlin is designed to interoperate fully with Java, and the Java virtual machine (JVM) version of Kotlin's standard library depends on the Java Class Library.
However, type inference allows for more concise syntax. Kotlin mainly targets the JVM, but also compiles to JavaScript (e.g., for frontend web applications using React) or native code via LLVM (e.g., for native iOS apps sharing business logic with Android apps). JetBrains bears language development costs, while the Kotlin Foundation protects the Kotlin trademark.

On 7 May 2019, Google announced Kotlin had become its preferred language for Android app developers. Since the release of Android Studio 3.0 in October 2017, Kotlin has been included as an alternative to the standard Java compiler. The Android Kotlin compiler emits Java 8 bytecode by default (which runs in any later JVM), but allows targeting Java 9 up to 24, for optimizing, or allows for more features; it has bidirectional record class interoperability support for JVM, introduced in Java 16, considered stable as of Kotlin 1.5.

Kotlin has support for the web with Kotlin/JS, through an intermediate representation-based backend that has been declared stable since version 1.8, released in December 2022. Kotlin/Native (e.g., Apple silicon support) has been declared stable since version 1.9.20, released in November 2023. (Full article...)

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...)

Steven Paul Jobs (February 24, 1955 – October 5, 2011) was an American businessman, inventor, and investor. A pioneer of the personal computer revolution of the 1970s and 1980s, Jobs co-founded Apple Inc. with his early business partner Steve Wozniak as Apple Computer Company in 1976. After the company's board of directors fired him in 1985, he founded NeXT the same year and purchased Pixar in 1986, becoming its chairman and majority shareholder until 2007. Jobs returned to Apple in 1997 as CEO, where he was closely involved with the creation and promotion of many of the company's most influential products until his resignation in 2011.

Jobs was born in San Francisco in 1955 and adopted shortly afterward. He attended Reed College in 1972 before withdrawing that same year. In 1974, he traveled through India, seeking enlightenment before later studying Zen Buddhism. He and Wozniak co-founded Apple in 1976 to further develop and sell Wozniak's Apple I personal computer. Together, the duo gained fame and wealth a year later with the production and sale of the Apple II, one of the first highly successful mass-produced microcomputers.

Jobs saw the commercial potential of the Xerox Alto in 1979, which was mouse-driven and had a graphical user interface (GUI). This led to the development of the largely unsuccessful Apple Lisa in 1983, followed by the breakthrough Macintosh 128K in 1984, the first mass-produced computer with a GUI. The Macintosh launched the desktop publishing industry in 1985 (for example, the Aldus PageMaker) with the addition of the Apple LaserWriter, the first laser printer to feature vector graphics and PostScript. (Full article...)

D, also known as dlang, is a multi-paradigm system programming language created by Walter Bright at Digital Mars and released in 2001. Andrei Alexandrescu joined the design and development effort in 2007. Though it originated as a re-engineering of C++, D is now a very different language. As it has developed, it has drawn inspiration from other high-level programming languages. Notably, it has been influenced by Java, Python, Ruby, C#, and Eiffel.

The D language reference describes it as follows: (Full article...)

COBOL (Common Business-Oriented Language; /ˈkoʊbɒl, -bɔːl/) is a compiled English-like computer programming language designed for business use. It is an imperative, procedural, and, since 2002, object-oriented language. COBOL is primarily used in business, finance, and administrative systems for companies and governments. COBOL is still widely used in applications deployed on mainframe computers, such as large-scale batch and transaction processing jobs. Many large financial institutions were developing new systems in the language as late as 2006, but most programming in COBOL today is purely to maintain existing applications. Programs are being moved to new platforms, rewritten in modern languages, or replaced with other software.

COBOL's design was started in 1959 by CODASYL and was partly based on the programming language FLOW-MATIC, designed by Grace Hopper. It was created as part of a US Department of Defense effort to create a portable programming language for data processing. It was originally seen as a stopgap, but the Defense Department promptly pressured computer manufacturers to provide it, resulting in its widespread adoption. It was standardized in 1968 and has been revised five times. Expansions include support for structured and object-oriented programming. The current standard is ISO/IEC 1989:2023.

COBOL statements have prose syntax such as MOVE x TO y, which was designed to be self-documenting and highly readable. However, it is verbose and uses over 300 reserved words compared to the succinct and mathematically inspired syntax of other languages. (Full article...)

Margaret Elaine Hamilton (née Heafield; born August 17, 1936) is an American computer scientist. She directed the Software Engineering Division at the MIT Instrumentation Laboratory, where she led the development of the on-board flight software for NASA's Apollo Guidance Computer for the Apollo program. She later founded two software companies, Higher Order Software in 1976 and Hamilton Technologies in 1986, both in Cambridge, Massachusetts.

Hamilton has published more than 130 papers, proceedings, and reports, about sixty projects, and six major programs. She coined the term "software engineering", stating, "I began to use the term 'software engineering' to distinguish it from hardware and other kinds of engineering, yet treat each type of engineering as part of the overall systems engineering process."

On November 22, 2016, Hamilton received the Presidential Medal of Freedom from president Barack Obama for her work leading to the development of on-board flight software for NASA's Apollo Moon missions. (Full article...)

The history of computing in the Soviet Union began in the late 1940s, when the country began to develop its Small Electronic Calculating Machine (MESM) at the Kiev Institute of Electrotechnology in Feofaniya. Initial ideological opposition to cybernetics in the Soviet Union was overcome by a Khrushchev era policy that encouraged computer production.

By the early 1970s, the uncoordinated work of competing government ministries had left the Soviet computer industry in disarray. Due to lack of common standards for peripherals and lack of digital storage capacity the Soviet Union's technology significantly lagged behind the West's semiconductor industry. The Soviet government decided to abandon development of original computer designs and encouraged cloning of existing Western systems (e.g. the 1801 CPU series was scrapped in favor of the PDP-11 ISA by the early 1980s).

Soviet industry was unable to mass-produce computers to acceptable quality standards and locally manufactured copies of Western hardware were unreliable. As personal computers spread to industries and offices in the West, the Soviet Union's technological lag increased. (Full article...)

Augusta Ada King, Countess of Lovelace (née Byron; 10 December 1815 – 27 November 1852), also known as Ada Lovelace, was an English mathematician and writer chiefly known for work on Charles Babbage's proposed mechanical general-purpose computer, the analytical engine. She was the first to recognise the machine had applications beyond pure calculation. Lovelace is often considered the first computer programmer.

Lovelace was the only legitimate child of poet Lord Byron and reformer Anne Isabella Milbanke. Lord Byron separated from his wife a month after Ada was born, and died when she was eight. Although often ill in childhood, Lovelace pursued her studies assiduously. She married William King in 1835. King was a Baron, and was created Viscount Ockham and 1st Earl of Lovelace in 1838. The name Lovelace was chosen because Ada was descended from the extinct Baron Lovelaces. The title given to her husband thus made Ada the Countess of Lovelace.

Lovelace's educational and social exploits brought her into contact with scientists such as Andrew Crosse, Charles Babbage, David Brewster, Charles Wheatstone and Michael Faraday, and the author Charles Dickens, contacts which she used to further her education. Lovelace described her approach as "poetical science" and herself as an "Analyst (& Metaphysician)". (Full article...)

In computing, assembly language (alternatively assembler language or symbolic machine code), often referred to simply as assembly and commonly abbreviated as ASM or asm, is any low-level programming language with a very strong correspondence between the instructions in the language and the architecture's machine code instructions. Assembly language usually has one statement per machine code instruction (1:1), but constants, comments, assembler directives, symbolic labels of, e.g., memory locations, registers, and macros are generally also supported.

The first assembly code in which a language is used to represent machine code instructions is found in Kathleen and Andrew Donald Booth's 1947 work, Coding for A.R.C.. Assembly code is converted into executable machine code by a utility program referred to as an assembler. The term "assembler" is generally attributed to Wilkes, Wheeler and Gill in their 1951 book The Preparation of Programs for an Electronic Digital Computer, who, however, used the term to mean "a program that assembles another program consisting of several sections into a single program". The conversion process is referred to as assembly, as in assembling the source code. The computational step when an assembler is processing a program is called assembly time.

Because assembly depends on the machine code instructions, each assembly language is specific to a particular computer architecture such as x86 or ARM. (Full article...)

Microsoft is a computer technology corporation. Microsoft was founded on April 4, 1975, by Bill Gates and Paul Allen in Albuquerque, New Mexico. Its current best-selling products are the Microsoft Windows operating system; Microsoft Office, a suite of productivity software; Xbox, a line of entertainment of games, music, and video; Bing, a line of search engines; and Microsoft Azure, a cloud services platform.

In 1980, Microsoft formed a partnership with IBM to bundle Microsoft's operating system with IBM computers; with that deal, IBM paid Microsoft a royalty for every sale. In 1985, IBM requested Microsoft to develop a new operating system for their computers called OS/2. Microsoft produced that operating system, but also continued to sell their own alternative, which proved to be in direct competition with OS/2. Microsoft Windows eventually overshadowed OS/2 in terms of sales. When Microsoft launched several versions of Microsoft Windows in the 1990s, they had captured over 90% market share of the world's personal computers.

As of June 30, 2015, Microsoft has a global annual revenue of US$86.83 billion (~$112 billion in 2024) and 128,076 employees worldwide. It develops, manufactures, licenses, and supports a wide range of software products for computing devices. (Full article...)

Stephen Gary Wozniak (/ˈwɒzniæk/; born August 11, 1950), also known by his nickname Woz, is an American technology entrepreneur, electrical engineer, computer programmer, and inventor. In 1976, he co-founded Apple Computer (now Apple Inc.) with his early business partner Steve Jobs. Through his work at Apple in the 1970s and 1980s, he is widely recognized as one of the most prominent pioneers of the personal computer revolution.

In 1975, Wozniak started developing the Apple I into the computer that launched Apple when he and Jobs first began marketing it the following year. He was the primary designer of the Apple II, introduced in 1977, known as one of the first highly successful mass-produced microcomputers, while Jobs oversaw the development of its foam-molded plastic case and early Apple employee Rod Holt developed its switching power supply.

With human–computer interface expert Jef Raskin, Wozniak had a major influence over the initial development of the original Macintosh concepts from 1979 to 1981, when Jobs took over the project following Wozniak's brief departure from the company due to a traumatic airplane accident. After permanently leaving Apple in 1985, Wozniak founded CL 9 and created the first programmable universal remote, released in 1987. He then pursued several other business and philanthropic ventures throughout his career, focusing largely on technology in K–12 schools, which involved a 1990 initiative to place computers in schools in the former Soviet Union. (Full article...)

A linker or link editor is a computer program that combines intermediate software build files such as object and library files into a single executable file such as a program or library. A linker is often part of a toolchain that includes a compiler and/or assembler that generates intermediate files that the linker processes. The linker may be integrated with other toolchain tools such that the user does not interact with the linker directly.

A simpler version that writes its output directly to memory is called the loader, though loading is typically considered a separate process. (Full article...)