C Programming at Wikibooks. C ( / ˈsiː /, as in the letter c) is a general-purpose, procedural computer programming language supporting structured programming, lexical variable scope, and recursion, with a static type system. By design, C provides constructs that map efficiently to typical machine instructions.
- Dennis Ritchie
Dennis MacAlistair Ritchie (September 9, 1941 – c. October...
- Lexical Variable Scope
In computer programming, the scope of a name binding—an...
- Dennis Ritchie
- C Standards
- Example Code
- Related Pages
- Other Websites
There are three successive standards for the C programming language ANSI C, ISO C and Standard Cwhich are published by the American National Standards Institute(ANSI) and the International Organization for Standardization(ISO). C is available for many different types of computers. This is why C is called a "portable" language. A program that is written in C and that respects certain limitations can be compiled for many different platforms. The syntax of C has also influenced many other programming languages, such as C++, C#, and Java, and many more programming languages we use nowadays.
Here is an example of a program written in C. When built and run it will show "Hello world!", followed by a new line on the computer screen. 1. #include gets the standard input/output tools ready for the program to use. This allows text to be displayed (output). 2. intmain()is called the main function, and it is where the first code starts being run in a C program. 3. printf("Hello world!\ ");is what displays text, in this case "Hello world!" with a new line (\ ) at the end. 4. return0;tells the computer that the program finished and did not run into problems.
- Design and Implementation
- Proprietary Languages
- Dialects, Flavors and Implementations
A programming language is a notation for writing programs, which are specifications of a computation or algorithm. Some authors restrict the term "programming language" to those languages that can express all possible algorithms.Traits often considered important for what constitutes a programming language include: Function and target 1. A computer programming language is a language used to write computer programs, which involves a computer performing some kind of computation or algorithm and possibly control external devices such as printers, disk drives, robots, and so on. For example, PostScript programs are frequently created by another program to control a computer printer or display. More generally, a programming language may describe computation on some, possibly abstract, machine. It is generally accepted that a complete specification for a programming language includes a description, possibly idealized, of a machine or processor for that language. In most practical contexts,...
Very early computers, such as Colossus, were programmed without the help of a stored program, by modifying their circuitry or setting banks of physical controls. Slightly later, programs could be written in machine language, where the programmer writes each instruction in a numeric form the hardware can execute directly. For example, the instruction to add the value in two memory locations might consist of 3 numbers: an "opcode" that selects the "add" operation, and two memory locations. The...
The increased use of high-level languages introduced a requirement for low-level programming languages or system programming languages. These languages, to varying degrees, provide facilities between assembly languages and high-level languages. They can be used to perform tasks that require direct access to hardware facilities but still provide higher-level control structures and error-checking. The period from the 1960s to the late 1970s brought the development of the major language paradigm...
Consolidation and growth
The 1980s were years of relative consolidation. C++ combined object-oriented and systems programming. The United States government standardized Ada, a systems programming language derived from Pascal and intended for use by defense contractors. In Japan and elsewhere, vast sums were spent investigating the so-called "fifth-generation" languages that incorporated logic programming constructs. The functional languages community moved to standardize MLand Lisp. Rather than inventing new paradigm...
All programming languages have some primitivebuilding blocks for the description of data and the processes or transformations applied to them (like the addition of two numbers or the selection of an item from a collection). These primitives are defined by syntactic and semantic rules which describe their structure and meaning respectively.
Programming languages share properties with natural languages related to their purpose as vehicles for communication, having a syntactic form separate from its semantics, and showing language families of related languages branching one from another. But as artificial constructs, they also differ in fundamental ways from languages that have evolved through usage. A significant difference is that a programming language can be fully described and studied in its entirety since it has a precise and finite definition. By contrast, natural languages have changing meanings given by their users in different communities. While constructed languagesare also artificial languages designed from the ground up with a specific purpose, they lack the precise and complete semantic definition that a programming language has. Many programming languages have been designed from scratch, altered to meet new needs, and combined with other languages. Many have eventually fallen into disuse. Although there ha...
Although most of the most commonly used programming languages have fully open specifications and implementations, many programming languages exist only as proprietary programming languages with the implementation available only from a single vendor, which may claim that such a proprietary language is their intellectual property. Proprietary programming languages are commonly domain specific languages or internal scripting languagesfor a single product; some proprietary languages are used only internally within a vendor, while others are available to external users. Some programming languages exist on the border between proprietary and open; for example, Oracle Corporation asserts proprietary rights to some aspects of the Java programming language, and Microsoft's C# programming language, which has open implementations of most parts of the system, also has Common Language Runtime(CLR) as a closed environment. Many proprietary languages are widely used, in spite of their proprietary n...
Thousands of different programming languages have been created, mainly in the computing field.Individual software projects commonly use five programming languages or more. Programming languages differ from most other forms of human expression in that they require a greater degree of precision and completeness. When using a natural language to communicate with other people, human authors and speakers can be ambiguous and make small errors, and still expect their intent to be understood. However, figuratively speaking, computers "do exactly what they are told to do", and cannot "understand" what code the programmer intended to write. The combination of the language definition, a program, and the program's inputs must fully specify the external behavior that occurs when the program is executed, within the domain of control of that program. On the other hand, ideas about an algorithm can be communicated to humans without the precision required for execution by using pseudocode, which in...
A dialect of a programming language or a data exchange language is a (relatively small) variation or extension of the language that does not change its intrinsic nature. With languages such as Scheme and Forth, standards may be considered insufficient, inadequate or illegitimate by implementors, so often they will deviate from the standard, making a new dialect. In other cases, a dialect is created for use in a domain-specific language, often a subset. In the Lisp world, most languages that use basic S-expression syntax and Lisp-like semantics are considered Lisp dialects, although they vary wildly, as do, say, Racket and Clojure. As it is common for one language to have several dialects, it can become quite difficult for an inexperienced programmer to find the right documentation. The BASIC programming language has many dialects. The explosion of Forth dialects led to the saying "If you've seen one Forth... you've seen oneForth."
There is no overarching classification scheme for programming languages. A given programming language does not usually have a single ancestor language. Languages commonly arise by combining the elements of several predecessor languages with new ideas in circulation at the time. Ideas that originate in one language will diffuse throughout a family of related languages, and then leap suddenly across familial gaps to appear in an entirely different family. The task is further complicated by the fact that languages can be classified along multiple axes. For example, Java is both an object-oriented language (because it encourages object-oriented organization) and a concurrent language (because it contains built-in constructs for running multiple threads in parallel). Python is an object-oriented scripting language. In broad strokes, programming languages divide into programming paradigms and a classification by intended domain of use, with general-purpose programming languages distinguis...
C++ (/ ˌ s iː ˌ p l ʌ s ˈ p l ʌ s /) is a general-purpose programming language created by Bjarne Stroustrup as an extension of the C programming language, or "C with Classes".The language has expanded significantly over time, and modern C++ now has object-oriented, generic, and functional features in addition to facilities for low-level memory manipulation.
- Design Goals
- Common Type System
- Standardization and Licensing
- Further Reading
- External Links
The Ecma standard lists these design goals for C#: 1. The language is intended to be a simple, modern, general-purpose, object-oriented programminglanguage. 2. The language, and implementations thereof, should provide support for software engineering principles such as strong type checking, array bounds checking, detection of attempts to use uninitialized variables, and automatic garbage collection. Software robustness, durability, and programmer productivity are important. 3. The language is intended for use in developing software components suitable for deploymentin distributed environments. 4. Portability is very important for source code and programmers, especially those already familiar with C and C++. 5. Support for internationalizationis very important. 6. C# is intended to be suitable for writing applications for both hosted and embedded systems, ranging from the very large that use sophisticated operating systems, down to the very small having dedicated functions. 7. Althou...
During the development of the .NET Framework, the class libraries were originally written using a managed code compiler system called "Simple Managed C" (SMC). In January 1999, Anders Hejlsberg formed a team to build a new language at the time called Cool, which stood for "C-like Object Oriented Language". Microsoft had considered keeping the name "Cool" as the final name of the language, but chose not to do so for trademark reasons. By the time the .NET project was publicly announced at the July 2000 Professional Developers Conference, the language had been renamed C#, and the class libraries and ASP.NETruntime had been ported to C#. Hejlsberg is C#'s principal designer and lead architect at Microsoft, and was previously involved with the design of Turbo Pascal, Embarcadero Delphi (formerly CodeGear Delphi, Inprise Delphi and Borland Delphi), and Visual J++. In interviews and technical papers he has stated that flaws in most major programming languages (e.g. C++, Java, Delphi, and...
The core syntax of the C# language is similar to that of other C-style languages such as C, C++ and Java, particularly: 1. Semicolons are used to denote the end of a statement. 2. Curly brackets are used to group statements. Statements are commonly grouped into methods (functions), methods into classes, and classes into namespaces. 3. Variables are assigned using an equals sign, but compared using two consecutive equals signs. 4. Square brackets are used with arrays, both to declare them and to get a value at a given index in one of them.
C# has a unified type system. This unified type system is called Common Type System(CTS). A unified type system implies that all types, including primitives such as integers, are subclasses of the System.Object class. For example, every type inherits a ToString()method.
The C# specification details a minimum set of types and class libraries that the compiler expects to have available. In practice, C# is most often used with some implementation of the Common Language Infrastructure (CLI), which is standardized as ECMA-335 Common Language Infrastructure (CLI). In addition to the standard CLI specifications, there are many commercial and community class libraries that build on top of the .NET framework libraries to provide additional functionality. C# can make calls to any library included in the List of .NET libraries and frameworks.
The following is a very simple C# program, a version of the classic "Hello world" example: Using C# 9 Top-level statementsfeature the entry point logic of a program can be written without declaring an explicit type or Main method.Until C# 8 remains the classic way: This code will display this text in the console window: Each line has a purpose: The above line imports all types in the System namespace. For example, the Console class used later in the source code is defined in the Systemnamespa...
A GUIexample: This example is similar to the previous example, except that it generates a dialog boxthat contains the message "Hello, World!" instead of writing it to the console.
Another useful library is the System.Drawinglibrary, which is used to programmatically draw images. For example: This will create an image that is identical to that stored in "Image.png".
In August 2001, Microsoft Corporation, Hewlett-Packard and Intel Corporation co-sponsored the submission of specifications for C# as well as the Common Language Infrastructure (CLI) to the standards organization Ecma International.In December 2001, ECMA released ECMA-334 C# Language Specification. C# became an ISO standard in 2003 (ISO/IEC 23270:2003 - Information technology — Programming languages — C#). ECMA had previously adopted equivalent specifications as the 2nd edition of C#, in December 2002. In June 2005, ECMA approved edition 3 of the C# specification, and updated ECMA-334. Additions included partial classes, anonymous methods, nullable types, and generics (somewhat similar to C++ templates). In July 2005, ECMA submitted to ISO/IEC JTC 1, via the latter's Fast-Track process, the standards and related TRs. This process usually takes 6–9 months. The C# language definition and the CLI are standardized under ISO and Ecma standards that provide reasonable and non-discriminator...
Microsoft is leading the development of the open-source reference C# compilers and set of tools. The first compiler, Roslyn, compiles into intermediate language (IL), and the second one, RyuJIT, is a JIT (just-in-time) compiler, which is dynamic and does on-the-fly optimization and compiles the IL into native code for the front-end of the CPU. RyuJIT is open source and written in C++. Roslyn is entirely written in managed code (C#), has been opened up and functionality surfaced as APIs. It is thus enabling developers to create refactoring and diagnostics tools. Two branches of official implementation are .NET Framework (closed source, Windows 10 only since .NET 4.6.2) and .NET Core (open source, multiplatform); .NET Framework and .NET Core converged into one open source implementation .NET 5.0.At .NET Framework 4.6 a new JIT compiler replaced the former. Other C# compilers (some of which include an implementation of the Common Language Infrastructureand .NET class libraries): 1. The...Drayton, Peter; Albahari, Ben; Neward, Ted (2002). C# Language Pocket Reference. O'Reilly. ISBN 0-596-00429-X.Petzold, Charles (2002). Programming Microsoft Windows with C#. Microsoft Press. ISBN 0-7356-1370-2.
A concurrent programming language for writing application software with interactive graphical ...LanguageYear StartedCreated By (at)Description/comments1966A procedural, imperative, and structured ...1969Designed for recursive, non-numeric, ...1969-1973Dennis Ritchie ( Bell Labs)Was an enhancement of Ken Thompson 's B ...1974Brian Kernighan (Bell Labs)A hybrid of C and Fortran, implemented as ...