The Computer Programming Portal
Sample of computer program 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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PHP is a general-purpose scripting language geared towards web development. It was originally created by Danish-Canadian programmer Rasmus Lerdorf in 1993 and released in 1995. The PHP reference implementation is now produced by the PHP Group. PHP was originally an abbreviation of Personal Home Page, but it now stands for the recursive backronym PHP: Hypertext Preprocessor.
PHP code is usually processed on a web server by a PHP interpreter implemented as a module, a daemon or a Common Gateway Interface (CGI) executable. On a web server, the result of the interpreted and executed PHP code—which may be any type of data, such as generated HTML or binary image data—would form the whole or part of an HTTP response. Various web template systems, web content management systems, and web frameworks exist that can be employed to orchestrate or facilitate the generation of that response. Additionally, PHP can be used for many programming tasks outside the web context, such as standalone graphical applications and drone control. PHP code can also be directly executed from the command line.
The standard PHP interpreter, powered by the Zend Engine, is free software released under the PHP License. PHP has been widely ported and can be deployed on most web servers on a variety of operating systems and platforms. (Full article...) -
Paul Gardner Allen (January 21, 1953 – October 15, 2018) was an American businessman, computer programmer, and investor. He co-founded Microsoft Corporation with his childhood friend Bill Gates in 1975, which was followed by the microcomputer revolution of the 1970s and 1980s. Allen was ranked as one of the richest people in American history by Forbes with an estimated net worth of $20.3 billion at the time of his death in October 2018.
Allen quit from day-to-day work at Microsoft in early 1983 after a Hodgkin lymphoma diagnosis, remaining on its board as vice-chairman. He and his sister, Jody Allen, founded Vulcan Inc. in 1986, a privately held company that managed his business and philanthropic efforts. At the time of his death, he had a multi-billion dollar investment portfolio, including technology and media companies, scientific research, real estate holdings, private space flight ventures, and stakes in other sectors. He owned the Seattle Seahawks of the National Football League and the Portland Trail Blazers of the National Basketball Association, and was part-owner of the Seattle Sounders FC of Major League Soccer. Under Allen's helm, the Seahawks won Super Bowl XLVIII and made it to two other Super Bowls (XL and XLIX). In 2000 he resigned from his position on Microsoft's board and assumed the post of senior strategy advisor to the company's management team.
Allen founded the Allen Institutes for Brain Science, Artificial Intelligence, and Cell Science, as well as companies like Stratolaunch Systems and Apex Learning. He gave more than $2 billion to causes such as education, wildlife and environmental conservation, the arts, healthcare, and community services. In 2004, he funded the first crewed private spaceplane with SpaceShipOne. He received numerous awards and honors, and was listed among the Time 100 Most Influential People in the World in 2007 and 2008. (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...) -
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...) -
In computer systems a loader is the part of an operating system that is responsible for loading programs and libraries. It is one of the essential stages in the process of starting a program, as it places programs into memory and prepares them for execution. Loading a program involves either memory-mapping or copying the contents of the executable file containing the program instructions into memory, and then carrying out other required preparatory tasks to prepare the executable for running. Once loading is complete, the operating system starts the program by passing control to the loaded program code.
All operating systems that support program loading have loaders, apart from highly specialized computer systems that only have a fixed set of specialized programs. Embedded systems typically do not have loaders, and instead, the code executes directly from ROM or similar. In order to load the operating system itself, as part of booting, a specialized boot loader is used. In many operating systems, the loader resides permanently in memory, though some operating systems that support virtual memory may allow the loader to be located in a region of memory that is pageable.
In the case of operating systems that support virtual memory, the loader may not actually copy the contents of executable files into memory, but rather may simply declare to the virtual memory subsystem that there is a mapping between a region of memory allocated to contain the running program's code and the contents of the associated executable file. (See memory-mapped file.) The virtual memory subsystem is then made aware that pages with that region of memory need to be filled on demand if and when program execution actually hits those areas of unfilled memory. This may mean parts of a program's code are not actually copied into memory until they are actually used, and unused code may never be loaded into memory at all. (Full article...) -
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...) -
The Greek lowercase omega (ω) character is used to represent Null in database theory.
In SQL, 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,NULLis 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, consider the question "How many books does Adam own?" The answer may be "zero" (we know that he owns none) or "null" (we do not know how many he owns). 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 is quite different from most programming languages, where a null value of a reference means it is not pointing to any object. (Full article...) -
Charles Babbage KH FRS (/ˈbæbɪdʒ/; 26 December 1791 – 18 October 1871) was an English polymath. A mathematician, philosopher, inventor and mechanical engineer, Babbage originated the concept of a digital programmable computer.
Babbage is considered by some to merit the title of "father of the computer". He is credited with inventing the first mechanical computer, the difference engine, that eventually led to more complex electronic designs, though all the essential ideas of modern computers are to be found in his analytical engine, programmed using a principle openly borrowed from the Jacquard loom. As part of his computer work, he also designed the first computer printers. He had a broad range of interests in addition to his work on computers, covered in his 1832 book Economy of Manufactures and Machinery. He was an important figure in the social scene in London, and is credited with importing the "scientific soirée" from France with his well-attended Saturday evening soirées. His varied work in other fields has led him to be described as "pre-eminent" among the many polymaths of his century.
Babbage, who died before the complete successful engineering of many of his designs, including his Difference Engine and Analytical Engine, remained a prominent figure in the ideating of computing. Parts of his incomplete mechanisms are on display in the Science Museum in London. In 1991, a functioning difference engine was constructed from the original plans. Built to tolerances achievable in the 19th century, the success of the finished engine indicated that Babbage's machine would have worked. (Full article...) -
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 current C++23 standard supersedes 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++26 as the next planned standard. (Full article...) -
Rust is a general-purpose programming language emphasizing performance, type safety, and concurrency. It enforces memory safety, meaning that all references point to valid memory. It does so 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.
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.
Software developer Graydon Hoare created Rust as a personal project while working at Mozilla Research in 2006. Mozilla officially sponsored the project in 2009. The first stable release of Rust, Rust 1.0, was published in May 2015. Following a large layoff of Mozilla employees in August 2020, multiple other companies joined Mozilla in sponsoring Rust through the creation of the Rust Foundation in February 2021. In December 2022, Rust became the first language other than C and assembly to be supported in the development of the Linux kernel. (Full article...) -
Julia is a dynamic general-purpose programming language. As a high-level language, distinctive aspects of Julia's design include a type system with parametric polymorphism, the use of multiple dispatch as a core programming paradigm, just-in-time (JIT) compilation and a parallel garbage collection implementation. Notably Julia does not support classes with encapsulated methods but instead relies on the types of all of a function's arguments to determine which method will be called.
By default, Julia is run similarly to scripting languages, using its runtime, and allows for interactions, but Julia programs/source code can also optionally be sent to users in one ready-to-install/run file, which can be made quickly, not needing anything preinstalled.
Julia programs can reuse libraries from other languages (or itself be reused from other); Julia has a special no-boilerplate keyword allowing calling e.g. C, Fortran or Rust libraries, and e.g. PythonCall.jl uses it indirectly for you, and Julia (libraries) can also be called from other languages, e.g. Python and R, and several Julia packages have been made easily available from those languages, in the form of Python and R libraries for corresponding Julia packages. Calling in either direction has been implemented for many languages, not just those and C++. (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 her work on Charles Babbage's proposed mechanical general-purpose computer, the Analytical Engine. She was the first to recognise that the machine had applications beyond pure calculation.
Lovelace was the only legitimate child of poet Lord Byron and reformer Anne Isabella Milbanke. All her half-siblings, Lord Byron's other children, were born out of wedlock to other women. Lord Byron separated from his wife a month after Ada was born and left England forever. He died in Greece whilst fighting in the Greek War of Independence, when she was eight. Lady Byron was anxious about her daughter's upbringing and promoted Lovelace's interest in mathematics and logic in an effort to prevent her from developing her father's perceived insanity. Despite this, Lovelace remained interested in her father, naming one son Byron and the other, for her father's middle name, Gordon. Upon her death, she was buried next to her father at her request. Although often ill in her childhood, Lovelace pursued her studies assiduously. She married William King in 1835. King was made Earl of Lovelace in 1838, Ada thereby becoming Countess of Lovelace.
Lovelace's educational and social exploits brought her into contact with scientists such as Andrew Crosse, Charles Babbage, Sir 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...) -
Portion of the calculating machine with a printing mechanism of the analytical engine, built by Charles Babbage, as displayed at the Science Museum (London)
The analytical engine was a proposed digital mechanical general-purpose computer designed by the 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...) -
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 structure of a computer system made from component parts. It can sometimes be a high-level description that ignores details of the implementation. At a more detailed level, the description may include the instruction set architecture design, microarchitecture design, logic design, and implementation. (Full article...) -
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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Output 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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A head crash on a modern hard disk drive -
Deep 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. -
A view of the GNU nano Text editor version 6.0 -
A lone house. An image made using Blender 3D. -
GNOME Shell, GNOME Clocks, Evince, gThumb and GNOME Files at version 3.30, in a dark theme -
Bill Gosper's Glider Gun in action -
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Grace 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). -
Animation of a Non-uniform rational B-spline surface. Modeled and rendered in Cobalt. -
Ada 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. -
Partial view of the Mandelbrot set. Step 1 of a zoom sequence: Gap between the "head" and the "body" also called the "seahorse valley". -
Stephen Wolfram is a British-American computer scientist, physicist, and businessman. He is known for his work in computer science, mathematics, and in theoretical physics. -
An IBM Port-A-Punch punched card -
Partial 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. -
Margaret Hamilton standing next to the navigation software that she and her MIT team produced for the Apollo Project. -
This image (when viewed in full size, 1000 pixels wide) contains 1 million pixels, each of a different color.
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Did you know? -
- ... that NATO was once targeted by a group of "gay furry hackers"?
- ... that the study of selection algorithms has been traced to an 1883 work of Lewis Carroll on how to award second place in single-elimination tournaments?
- ... that a "hacker" with blog posts written by ChatGPT was at the center of an online scavenger hunt promoting Avenged Sevenfold's album Life Is but a Dream...?
- ... that Phil Fletcher as Hacker T. Dog caused Lauren Layfield to make the "most famous snort" in the United Kingdom in 2016?
- ... that a pink skin for Mercy in the video game Overwatch helped raise more than $12 million for breast cancer research?
- ... that it took a particle accelerator and machine-learning algorithms to extract the charred text of PHerc. Paris. 4 without unrolling it?
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