Citizendia

C
Paradigmimperative (procedural) systems implementation language
Appeared in1972
Designed byDennis Ritchie
DeveloperDennis Ritchie & Bell Labs
Turing-completeYes
Typing disciplinestatic, weak
Major implementationsGCC, MSVC, Borland C, Watcom C
Influenced byB (BCPL,CPL), ALGOL 68[1] , Assembly, PL/I, FORTRAN
Influencedawk, csh, C++, C#, Objective-C, BitC, D, Java, JavaScript, Limbo, Perl, PHP, Python

C is a general-purpose, block structured, procedural, imperative computer programming language developed in 1972 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system. A programming paradigm is a fundamental style of Computer programming. In Computer science, imperative programming is a Programming paradigm that describes computation in terms of statements that change a program state Procedural programming can sometimes be used as a synonym for Imperative programming (specifying the steps the program must take to reach the desired state but can also Year 1972 ( MCMLXXII) was a Leap year starting on Saturday (link will display full calendar of the Gregorian calendar. Dennis MacAlistair Ritchie (born September 9, 1941) is an American computer scientist notable for his influence on C and other Programming A software developer is a person or organization concerned with facets of the software development process wider than design and coding a somewhat broader scope of Dennis MacAlistair Ritchie (born September 9, 1941) is an American computer scientist notable for his influence on C and other Programming Bell Laboratories (also known as Bell Labs and formerly known as AT&T Bell Laboratories and Bell Telephone Laboratories) is the Research organization In computability theory, several closely-related terms are used to describe the "computational power" of a computational system (such as an Abstract machine or In Computer science, a type system defines how a Programming language classifies values and expressions into '''types''', how it can In Computer science, a type system defines how a Programming language classifies values and expressions into '''types''', how it can In Computer science, weak typing (aka loose typing) is a property attributed to the Type systems of some Programming languages It is the opposite Implementation is the realization of an application or execution of a Plan, idea Model, Design, Specification, standard, Algorithm The GNU Compiler Collection (usually shortened to GCC) is a set of Compilers produced for various Programming languages by the GNU Project Microsoft Visual C++ (often abbreviated as MSVC) is a commercial Integrated development environment (IDE product engineered by Microsoft for the Due to technical limitations "Turbo C#" redirects here The Watcom C / C++ compiler is esteemed amongst DOS developers by the high execution speed of the compiled code it produces and for having been B is a programming language that was developed at Bell Labs. It is almost extinct as it was replaced by the C language. The Combined Programming Language (CPL was a computer Programming language developed jointly between the Mathematical Laboratory at the University of Cambridge and Time-line of ALGOL 68 The Algorithmic Language ALGOL 68 Reports Mar See the terminology section below for information regarding inconsistent use of the terms assembly and assembler PL/I ("Programming Language One" ˌpiːˌɛlˈwʌn is an imperative computer Programming language designed for scientific engineering Fortran (previously FORTRAN) is a general-purpose, procedural, imperative Programming language that is especially suited to AWK is a general purpose Programming language that is designed for processing text-based data either in files or data streams and was created at Bell Labs in the 1970s The C shell ( csh) is a Unix shell developed by Bill Joy for the BSD Unix system C++ (" C Plus Plus " ˌsiːˌplʌsˈplʌs is a general-purpose Programming language. C# (pronounced C Sharp is a Multi-paradigm Objective-C is a reflective, object-oriented Programming language which adds Smalltalk -style messaging to C. BitC is a Programming language currently being developed by researchers at the Johns Hopkins University and The EROS Group LLC as part of the Coyotos The D programming language, also known simply as D, is an object-oriented, imperative, multiparadigm System programming language JavaScript is a Scripting language most often used for Client-side web development Limbo is a Programming language for writing distributed systems and is the language used to write applications for the Inferno Operating system NOTES FOR EDITORS "Perl" is not an acronym (read the "Name" section below PHP is a computer Scripting language. Originally designed for producing Dynamic web pages it has evolved to include a Command line interface capability Python is a general-purpose High-level programming language. Its design philosophy emphasizes programmer productivity and code readability In Computer programming, a statement block (or code block) is a section of code which is grouped together much like a Paragraph; such blocks Procedural programming can sometimes be used as a synonym for Imperative programming (specifying the steps the program must take to reach the desired state but can also In Computer science, imperative programming is a Programming paradigm that describes computation in terms of statements that change a program state A programming language is an Artificial language that can be used to write programs which control the behavior of a machine particularly a Computer. Dennis MacAlistair Ritchie (born September 9, 1941) is an American computer scientist notable for his influence on C and other Programming Bell Laboratories (also known as Bell Labs and formerly known as AT&T Bell Laboratories and Bell Telephone Laboratories) is the Research organization Unix (officially trademarked as UNIX, sometimes also written as Unix with Small caps) is a computer An operating system (commonly abbreviated OS and O/S) is the software component of a Computer system that is responsible for the management and coordination [2] It has since spread to many other platforms. Although C was designed as a system implementation language,[3][4] it is also widely used for applications. System software is any Computer software which manages and controls Computer hardware so that Application software can perform a task Application software is a subclass of Computer software that employs the capabilities of a computer directly and thoroughly to a task that the user wishes to perform C has also greatly influenced many other popular languages,[5] especially C++, which was originally designed as an extension to C. C++ (" C Plus Plus " ˌsiːˌplʌsˈplʌs is a general-purpose Programming language.

Contents

Philosophy

C is an imperative (procedural) systems implementation language. In Computer science, imperative programming is a Programming paradigm that describes computation in terms of statements that change a program state Procedural programming can sometimes be used as a synonym for Imperative programming (specifying the steps the program must take to reach the desired state but can also Systems programming (or system programming) is the activity of Programming System software. Its design goals were for it to be compiled using a relatively straightforward compiler, provide low-level access to memory, provide language constructs that map efficiently to machine instructions, and require minimal run-time support. A compiler is a Computer program (or set of programs that translates text written in a computer language (the source language) into another In Computer science, runtime or run time describes the operation of a Computer program, the duration of its execution from beginning to termination C was therefore useful for many applications that had formerly been coded in assembly language. See the terminology section below for information regarding inconsistent use of the terms assembly and assembler

Despite its low-level capabilities, the language was designed to encourage machine-independent programming. In computing cross-platform (also known as multi-platform) is a term used to refer to Computer software or computing methods and concepts that are implemented A standards-compliant and portably written C program can be compiled for a very wide variety of computer platforms and operating systems with minimal change to its source code. See also Software portability In Computer science, porting is the process of adapting software so that an executable program can be created The language has become available on a very wide range of platforms, from embedded microcontrollers to supercomputers.

Characteristics

Like most imperative languages in the ALGOL tradition, C has facilities for structured programming and allows lexical variable scope and recursion, while a static type system prevents many unintended operations. Algol (β Per / Beta Persei known colloquially as the Demon Star, is a bright Star in the Constellation Perseus. Structured programming can be seen as a subset or subdiscipline of Procedural programming, one of the major Programming paradigms It is most famous for removing or In Computer programming, scope is an enclosing context where values and expressions are associated Recursion, in Mathematics and Computer science, is a method of defining functions in which the function being defined is applied within its own definition In Computer science, a type system defines how a Programming language classifies values and expressions into '''types''', how it can In C, all executable code is contained within functions. In Computer science, a subroutine ( function, method, procedure, or subprogram) is a portion of code within a larger Function parameters are always passed by value. In Computer programming, a parameter is a variable which takes on the meaning of a corresponding Argument (computer science is same article--> argument Pass-by-reference is achieved in C by explicitly passing pointer values. Heterogeneous aggregate data types (struct) allow related data elements to be combined and manipulated as a unit. In Computer science, object composition (not to be confused with function composition) is a way and practice to combine simple objects or C program source text is free-format, using the semicolon as a statement terminator (not a delimiter).

C also exhibits the following more specific characteristics:

History

Early developments

The initial development of C occurred at AT&T Bell Labs between 1969 and 1973; according to Ritchie, the most creative period occurred in 1972. Before proposing a merge request please see Talk and see if the merger you propose has recently been made and Bell Laboratories (also known as Bell Labs and formerly known as AT&T Bell Laboratories and Bell Telephone Laboratories) is the Research organization It was named "C" because many of its features were derived from an earlier language called "B", which according to Ken Thompson was a stripped down version of the BCPL programming language. B is a programming language that was developed at Bell Labs. It is almost extinct as it was replaced by the C language. Kenneth Lane Thompson (born February 4 1943) commonly referred to as Ken Thompson (or simply

The origin of C is closely tied to the development of the Unix operating system, originally implemented in assembly language on a PDP-7 by Ritchie and Thompson, incorporating several ideas from colleagues. Unix (officially trademarked as UNIX, sometimes also written as Unix with Small caps) is a computer The DEC PDP-7 is a Minicomputer produced by Digital Equipment Corporation. Eventually they decided to port the operating system to a PDP-11. The PDP-11 was a series of 16-bit Minicomputers sold by Digital Equipment Corp B's lack of functionality to take advantage of some of the PDP-11's features, notably byte addressability, led to the development of an early version of the C programming language. A byte (pronounced "bite" baɪt is the basic unit of measurement of information storage in Computer science.

The original PDP-11 version of the Unix system was developed in assembly language. By 1973, with the addition of struct types, the C language had become powerful enough that most of the Unix kernel was rewritten in C. Unix (officially trademarked as UNIX, sometimes also written as Unix with Small caps) is a computer In Computer science, the kernel is the central component of most computer Operating systems (OS This was one of the first operating system kernels implemented in a language other than assembly. (Earlier instances include the Multics system (written in PL/I), and MCP (Master Control Program) for the Burroughs B5000 written in ALGOL in 1961. Multics ( Mult iplexed I nformation and C omputing S ervice was an extremely influential early Time-sharing Operating system PL/I ("Programming Language One" ˌpiːˌɛlˈwʌn is an imperative computer Programming language designed for scientific engineering The MCP (Master Control Program is the proprietary Operating system of the Burroughs large systems including the Unisys Clearpath/MCP The Burroughs large systems were the largest of three series of Burroughs Corporation mainframe computers Algol (β Per / Beta Persei known colloquially as the Demon Star, is a bright Star in the Constellation Perseus. )

K&R C

In 1978, Brian Kernighan and Dennis Ritchie published the first edition of The C Programming Language. Brian Wilson Kernighan (ˈkɛrnɪhæn the 'g' is silent (born 1942 Toronto, Ontario, Canada) is a Computer scientist who worked at Dennis MacAlistair Ritchie (born September 9, 1941) is an American computer scientist notable for his influence on C and other Programming The C Programming Language (sometimes referred to as K&R or the white book) is a well-known Computer science Book This book, known to C programmers as "K&R", served for many years as an informal specification of the language. The version of C that it describes is commonly referred to as "K&R C". The second edition of the book covers the later ANSI C standard. ANSI C is the standard published by the American National Standards Institute (ANSI for the C programming language.

K&R introduced several language features:

Even after the publication of the 1989 C standard, for many years K&R C was still considered the "lowest common denominator" to which C programmers restricted themselves when maximum portability was desired, since many older compilers were still in use, and because carefully written K&R C code can be legal Standard C as well.

In early versions of C, only functions that returned a non-integer value needed to be declared if used before the function definition; a function used without any previous declaration was assumed to return an integer, if its value was used.

For example:

long int SomeFunction();/* int OtherFunction(); *//* int */ CallingFunction(){    long int test1;    register /* int */ test2;    test1 = SomeFunction();    if (test1 > 0)           test2 = 0;    else           test2 = OtherFunction();    return test2;}

All the above commented-out int declarations could be omitted in K&R C.

Since K&R function declarations did not include any information about function arguments, function parameter type checks were not performed, although some compilers would issue a warning message if a local function was called with the wrong number of arguments, or if multiple calls to an external function used different numbers or types of arguments. In Computer science, a type system defines how a Programming language classifies values and expressions into '''types''', how it can Separate tools such as Unix's lint utility were developed that (among other things) could check for consistency of function use across multiple source files. In Computer programming, lint was the name originally given to a particular program that flagged suspicious and non-portable constructs (likely to be bugs in C language

In the years following the publication of K&R C, several unofficial features were added to the language, supported by compilers from AT&T and some other vendors. These included:

The large number of extensions and lack of agreement on a standard library, together with the language popularity and the fact that not even the Unix compilers precisely implemented the K&R specification, led to the necessity of standardization. The void type, in several programming languages derived from C and Algol68, is the type for the result of a function that produces no direct result In Computer science, object composition (not to be confused with function composition) is a way and practice to combine simple objects or In Computer science, a union is a Data structure that stores one of several types of data at a single location In Computer science the assignment statement sets or re-sets the value stored in the storage location(s denoted by a Variable Name. In Computer programming, an enumerated type is a Data type (usually user-defined consisting of a set of named constants called enumerators. The C standard library (also known as libc) is a now-standardized collection of Header files and library routines used to implement common operations such

ANSI C and ISO C

During the late 1970s and 1980s, versions of C were implemented for a wide variety of mainframe computers, minicomputers, and microcomputers, including the IBM PC, as its popularity began to increase significantly. Mainframes (often colloquially referred to as Big Iron) are Computers used mainly by large organizations for critical applications typically bulk data A minicomputer (colloquially mini) is a class of multi-user Computers that lies in the middle range of the computing spectrum in between the largest Multi-user microcomputer is a Computer with a Microprocessor as its Central processing unit.

In 1983, the American National Standards Institute (ANSI) formed a committee, X3J11, to establish a standard specification of C. In 1989, the standard was ratified as ANSI X3. 159-1989 "Programming Language C. " This version of the language is often referred to as ANSI C, Standard C, or sometimes C89. ANSI C is the standard published by the American National Standards Institute (ANSI for the C programming language.

In 1990, the ANSI C standard (with a few minor modifications) was adopted by the International Organization for Standardization (ISO) as ISO/IEC 9899:1990. This version is sometimes called C90. Therefore, the terms "C89" and "C90" refer to essentially the same language.

One of the aims of the C standardization process was to produce a superset of K&R C, incorporating many of the unofficial features subsequently introduced. However, the standards committee also included several new features, such as function prototypes (borrowed from C++), void pointers, support for international character sets and locales, and preprocessor enhancements. A function prototype in C or C++ is a declaration of a function that omits the function body but does specify the function's name Arity, argument A character encoding consists of a code that pairs a sequence of characters from a given character set (sometimes incorrectly referred to as Code page In Computing, locale is a set of Parameters that defines the user's language country and any special variant preferences that the user wants to see in their User The syntax for parameter declarations was also augmented to include the C++ style:

int main(int argc, char **argv){. . . }

although the K&R interface

int main(argc, argv)    int argc;    char **argv;{. . . }

continued to be permitted, for compatibility with existing source code.

C89 is supported by current C compilers, and most C code being written nowadays is based on it. Any program written only in Standard C and without any hardware-dependent assumptions will run correctly on any platform with a conforming C implementation, within its resource limits. In Computing, a platform describes some sort of Hardware architecture or Software framework (including Application frameworks, that allows Without such precautions, programs may compile only on a certain platform or with a particular compiler, due, for example, to the use of non-standard libraries, such as GUI libraries, or to a reliance on compiler- or platform-specific attributes such as the exact size of data types and byte endianness.

In cases where code must be compilable by either standard-conforming or K&R C-based compilers, the __STDC__ macro can be used to split the code into Standard and K&R sections to take advantage of features available only in Standard C. 

#ifdef __STDC__extern int getopt(int,char * const *,const char *);#elseextern int getopt();#endif

In the above example, a compiler which has defined the __STDC__ macro (as mandated by the C standard) only interprets the line following the ifdef command. In other, nonstandard compilers which don't define the macro, only the line following the else command is interpreted.

C99

Note: C99 is also the name of a C compiler for the Texas Instruments TI-99/4A home computer. The Texas Instruments TI-99/4A was an early Home computer, released in June 1981 originally at a price of USD $525 A home computer was a class of Personal computer entering the market in 1977 and becoming common during the 1980s Aside from being a C compiler, it is otherwise unrelated.

After the ANSI standardization process, the C language specification remained relatively static for some time, whereas C++ continued to evolve, largely during its own standardization effort. C++ (" C Plus Plus " ˌsiːˌplʌsˈplʌs is a general-purpose Programming language. Normative Amendment 1 created a new standard for the C language in 1995, but only to correct some details of the C89 standard and to add more extensive support for international character sets. However, the standard underwent further revision in the late 1990s, leading to the publication of ISO/IEC 9899:1999 in 1999. This standard is commonly referred to as "C99. " It was adopted as an ANSI standard in May 2000. The international C standard is maintained by the working group ISO/IEC JTC1/SC22/WG14. Working Group can mean Working group, an interdisciplinary group of researchers or Working Group (dogs, kennel club designation for SC22, or to give it its full title ISO/IEC JTC1 /SC22 is the international standardization subcommittee for Programming languages their environments and

New features

C99 introduced several new features, many of which had already been implemented as extensions in several compilers:

Backward compatibility with C90

C99 is for the most part backward compatible with C90, but is stricter in some ways; in particular, a declaration that lacks a type specifier no longer has int implicitly assumed. The IEEE Standard for Binary Floating-Point Arithmetic ( IEEE 754) is the most widely-used standard for floating-point computation and is followed by many A variadic macro is a feature of the C preprocessor whereby a macro may be declared to accept a varying number of arguments. In Logic, Mathematics, and Computer science, the arity (synonyms include type, adicity, and rank) of a function In the C programming language, as of the C99 standard restrict is a keyword which may be used when declaring pointers The restrict In Computing, optimization is the process of modifying a system to make some aspect of it work more efficiently or use fewer resources The C standards committee decided that it was of more value for compilers to diagnose inadvertent omission of the type specifier than to silently process legacy code that relied on implicit int. In practice, compilers are likely to diagnose the omission but also assume int and continue translating the program.

Support by major compilers

GCC and other C compilers now support many of the new features of C99. The GNU Compiler Collection (usually shortened to GCC) is a set of Compilers produced for various Programming languages by the GNU Project However, there has been less support from vendors such as Microsoft and Borland that have mainly focused on C++, since C++ provides similar functionality improvement. Microsoft Corporation is an American multinational Computer technology Corporation, which rose to dominate the Home computer Borland Software Corporation is a software company headquartered in Austin Texas.

GCC, despite its extensive C99 support, is still not a completely compliant implementation; several key features are missing or do not work correctly. [6]

According to Sun Microsystems, Sun Studio (which is freely downloadable) now supports the full C99 standard. Sun Microsystems Inc ( is a multinational vendor of Computers computer components Computer software, and Information technology services The Sun Studio compiler suite is Sun Microsystems ' flagship software development product for Solaris and Linux. [7]

Version detection

A standard macro __STDC_VERSION__ is defined with value 199901L to indicate that C99 support is available. As with the __STDC__ macro for C90, __STDC_VERSION__ can be used to write code that will compile differently for C90 and C99 compilers, as in this example that ensures that inline is available in either case. 

#if __STDC_VERSION__ >= 199901L  /* "inline" is a keyword */#else# define inline /* nothing */#endif

Future standards directions

Since ratification of the 1999 C standard, the standards working group has prepared technical reports specifying improved support for embedded processing, additional character data types (Unicode support), and library functions with improved bounds checking. In Computing, Unicode is an Industry standard allowing Computers to consistently represent and manipulate text expressed in most of the world's In Computer programming, bounds checking is any method of detecting whether a variable is within some bounds before its use Work continues on technical reports addressing decimal floating point, additional mathematical special functions, and additional dynamic memory allocation functions. In Computing, floating point describes a system for numerical representation in which a string of digits (or Bits represents a Real number. Special functions are particular mathematical functions which have more or less established names and notations due to their importance for the Mathematical analysis In Computer science, dynamic memory allocation is the allocation of memory storage for use in a Computer program during the Runtime of that program The C and C++ standards committees have been collaborating on specifications for threaded programming. A thread in Computer science is short for a thread of execution.

As of 2007, work has begun in anticipation of another revision of the C standard, informally called "C1x". Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. The C standards committee has adopted guidelines that should limit the adoption of new features that have not been not tested by existing implementations.

It is likely that the standard gets function, which was officially deprecated in response to a defect report concerning its unsafe interface design, will not be specified in the next revision of the C standard. gets is a function in the C standard library, declared in the Header file Stdio

Uses

C's primary use is for "system programming", including implementing operating systems and embedded system applications, due to a combination of desirable characteristics such as code portability and efficiency, ability to access specific hardware addresses, ability to "pun" types to match externally imposed data access requirements, and low runtime demand on system resources. Systems programming (or system programming) is the activity of Programming System software. An operating system (commonly abbreviated OS and O/S) is the software component of a Computer system that is responsible for the management and coordination An embedded system is a special-purpose Computer system designed to perform one or a few dedicated functions often with Real-time computing constraints __FORCETOC__In Computer science, type punning is a common term for any programming technique that subverts or circumvents the Type system of a Programming language In Computer science, runtime or run time describes the operation of a Computer program, the duration of its execution from beginning to termination

C has also been widely used to implement end-user applications, although as applications became larger much of that development shifted to other, higher-level languages. The end-user is a p concept in Software engineering, referring to an Abstraction of the group of persons who will ultimately operate a piece of software

One consequence of C's wide acceptance and efficiency is that the compilers, libraries, and interpreters of other higher-level languages are often implemented in C.

C is used as an intermediate language by some implementations of higher-level languages, which translate the input language to C source code, perhaps along with other object representations. In Computer science, an intermediate language is the language of an Abstract machine designed to aid in the analysis of Computer programs The term comes The C source code is compiled by a C compiler to produce object code. This approach may be used to gain portability (C compilers exist for nearly all platforms) or for convenience (it avoids having to develop machine-specific code generators). Some programming languages which use C this way are Eiffel, Esterel, Gambit, the Glasgow Haskell Compiler, Lisp dialects, Lush, Sather, Squeak, and Vala. Eiffel is an ISO -standardized Object-oriented Programming language designed to enable programmers to efficiently develop extensible reusable reliable Esterel is a synchronous Programming language for the development of complex Reactive systems The Imperative programming style of Gambit, also called Gambit-C is a Free software Scheme Implementation, consisting of a Scheme interpreter, and a Compiler which The Glorious Glasgow Haskell Compilation System, more commonly known as the Glasgow Haskell Compiler or GHC, is an Open source native code Lisp (or LISP) is a family of Computer Programming languages with a long history and a distinctive fully parenthesized syntax Lush, (Lisp Universal Shell is an object-oriented dialect of the Lisp programming language that was initially developed as a Scripting language for Sather is an Object-oriented Programming language. It originated circa 1990 at the International Computer Science Institute at the University of California The Squeak Programming language is a Smalltalk implementation derived directly from Smalltalk-80 by a group at Apple Computer that included some of the original Smalltalk-80 Vala is a programming language that tries to bring modern language features to C, without additional runtime requirements and with little overhead by targeting the GObject

Unfortunately, C was designed as a programming language, not as a compiler target language, and is thus less than ideal for use as an intermediate language. This has led to development of C-based intermediate languages such as C--. C-- is a C -like Programming language. Its creators Functional programming researchers Simon Peyton Jones and Norman Ramsey,

Syntax

Main article: C syntax

Unlike languages such as FORTRAN 77, C source code is free-form which allows arbitrary use of whitespace to format code, rather than column-based or text-line-based restrictions. The Syntax of the C programming language is a set of rules that specifies whether the sequence of characters in a file is conforming C Source code. Fortran (previously FORTRAN) is a general-purpose, procedural, imperative Programming language that is especially suited to In Computer programming, a free-form language is a Programming language in which the positioning of characters on the page in program text is not significant Comments may appear either between the delimiters /* and */, or (in C99) following // until the end of the line.

Each source file contains declarations and function definitions. Function definitions, in turn, contain declarations and statements. Declarations either define new types using keywords such as struct, union, and enum, or assign types to and perhaps reserve storage for new variables, usually by writing the type followed by the variable name. Keywords such as char and int specify built-in types. Sections of code are enclosed in braces ({ and }) to limit the scope of declarations and to act as a single statement for control structures. Brackets are Punctuation marks used in pairs to set apart or interject text within other text

As an imperative language, C uses statements to specify actions. The most common statement is an expression statement, consisting of an expression to be evaluated, followed by a semicolon; as a side effect of the evaluation, functions may be called and variables may be assigned new values. In Computer science, a subroutine ( function, method, procedure, or subprogram) is a portion of code within a larger In Computer science the assignment statement sets or re-sets the value stored in the storage location(s denoted by a Variable Name. To modify the normal sequential execution of statements, C provides several control-flow statements identified by reserved keywords. Structured programming is supported by if(-else) conditional execution and by do-while, while, and for iterative execution (looping). Structured programming can be seen as a subset or subdiscipline of Procedural programming, one of the major Programming paradigms It is most famous for removing or The for statement has separate initialization, testing, and reinitialization expressions, any or all of which can be omitted. break and continue can be used to leave the innermost enclosing loop statement or skip to its reinitialization. There is also a non-structured goto statement which branches directly to the designated label within the function. switch selects a case to be executed based on the value of an integer expression.

Expressions can use a variety of built-in operators (see below) and may contain function calls. The order in which operands to most operators, as well as the arguments to functions, are evaluated is unspecified; the evaluations may even be interleaved. However, all side effects (including storage to variables) will occur before the next "sequence point"; sequence points include the end of each expression statement and the entry to and return from each function call. A sequence point in Imperative programming defines any point in a Computer program 's execution at which it is guaranteed that all side effects This permits a high degree of object code optimization by the compiler, but requires C programmers to exert more care to obtain reliable results than is needed for other programming languages.

C Operators

Main article: Operators in C and C++

C supports a rich set of operators, which are symbols used within an expression to specify the manipulations to be performed while evaluating that expression. This is a list of operators in the C++ and C programming languages. Programming languages generally support a set of operators that are similar to operators in mathematics. An expression in a Programming language is a combination of values Variables operators and functions that are interpreted ( C has operators for:

Operator precedence and associativity

What follows is the list of C operators sorted from highest to lowest priority (precedence). Operators of same priority are presented on the same line. (That the post-increment operator (++) has higher priority than the dereference operator (*) means that an expression *p++ is grouped as *(p++) and not (*p)++. That the subtraction operator (-) has left-to-right associativity means that an expression a-b-c is grouped as (a-b)-c and not a-(b-c). )

ClassAssociativityOperators
GroupingNesting(expr)
PostfixLeft-to-Right(args)  []  −>  .   expr++  expr−−  
UnaryRight-to-Left!  ~  +  −  *  &  (typecast)  sizeof  ++expr  −−expr
MultiplicativeLeft-to-Right*  /  %
AdditiveLeft-to-Right+  −
ShiftLeft-to-Right<<  >>
RelationalLeft-to-Right<  <=  >  >=
EqualityLeft-to-Right==  !=
Bitwise ANDLeft-to-Right&
Bitwise XORLeft-to-Right^
Bitwise ORLeft-to-Right|
Logical ANDLeft-to-Right&&
Logical ORLeft-to-Right||
ConditionalRight-to-Left?:
AssignmentRight-to-Left=  +=  −=  *=  /=  %=  &=  |=  ^=  <<=  >>=
SequenceLeft-to-Right,

"Hello, world" example

The following simple application appeared in the first edition of K&R, and has become the model for an introductory program in most programming textbooks, regardless of programming language. The C Programming Language (sometimes referred to as K&R or the white book) is a well-known Computer science Book The program prints out "hello, world" to the standard output, which is usually a terminal or screen display. A "Hello World" program is a Computer program that prints out "Hello world!" on a Display device. In Unix and Unix-like operating systems as well as certain Programming language interfaces the standard streams are preconnected input and output channels Standard output might also be a file or some other hardware device, depending on how standard output is mapped at the time the program is executed. 

main(){    printf("hello, world\n");}

The above program will compile on most modern compilers that are not in compliance mode, but does not meet the requirements of either C89 or C99. Compiling this program in C99 compliance mode will result in warning or error messages. [8] A compliant version of the above program follows:

#include <stdio. h>int main(void){    printf("hello, world\n");    return 0;}

What follows is a line-by-line analysis of the above program:

#include <stdio. h>

This first line of the program is a preprocessing directive, #include. In Computer science, a preprocessor is a program that processes its input data to produce output that is used as input to another program This causes the preprocessor — the first tool to examine source code as it is compiled — to substitute the line with the entire text of the stdio. h file. The header file stdio. h contains declarations for standard input and output functions such as printf. The angle brackets surrounding stdio. h indicate that stdio. h can be found using an implementation-defined search strategy. Double quotes may also be used for headers, thus allowing the implementation to supply (up to) two strategies. Typically, angle brackets are reserved for headers supplied by the C compiler, and double quotes for local or installation-specific headers. 

int main(void)

This next line indicates that a function named main is being defined. The main function serves a special purpose in C programs: The run-time environment calls the main function to begin program execution. See also Entry point In some Programming languages the main function is where a program starts execution The type specifier int indicates that the return value, the value of evaluating the main function that is returned to its invoker (in this case the run-time environment), is an integer. The keyword void as a parameter list indicates that the main function takes no arguments. [9]

{

This opening curly brace indicates the beginning of the definition of the main function. 

    printf("hello, world\n");

This line calls (executes the code for) a function named printf, which is declared in the included header stdio. The class of printf functions (which stands for " print f ormatted" is a class of functions, typically associated with Curly bracket programming h and supplied from a system library. In Computer science, a library is a collection of Subroutines used to develop Software. In this call, the printf function is passed (provided with) a single argument, the address of the first character in the string literal "hello, world\n". The string literal is an unnamed array with elements of type char, set up automatically by the compiler with a final 0-valued character to mark the end of the array (printf needs to know this). In Computer science an array is a Data structure consisting of a group of elements that are accessed by indexing. The \n is an escape sequence that C translates to the newline character, which on output signifies the end of the current line. In Computing, a newline (also known as a line break or end-of-line / EOL character is a special character or sequence of characters The return value of the printf function is of type int, but it is silently discarded since it is not used by the caller. (A more careful program might test the return value to determine whether or not the printf function succeeded. ) The semicolon ; terminates the statement. 

    return 0;

This line terminates the execution of the main function and causes it to return the integer value 0, which is interpreted by the run-time system as an exit code (indicating successful execution). 

}

This closing curly brace indicates the end of the code for the main function.

Data structures

C has a static weak typing type system that shares some similarities with that of other ALGOL descendants such as Pascal. In Computer science, weak typing (aka loose typing) is a property attributed to the Type systems of some Programming languages It is the opposite In Computer science, a type system defines how a Programming language classifies values and expressions into '''types''', how it can Algol (β Per / Beta Persei known colloquially as the Demon Star, is a bright Star in the Constellation Perseus. Pascal is an influential imperative and procedural Programming language, designed in 1968/9 and published in 1970 by Niklaus Wirth as a small There are built-in types for integers of various sizes, both signed and unsigned, floating-point numbers, characters, and enumerated types (enum). In Computing, floating point describes a system for numerical representation in which a string of digits (or Bits represents a Real number. C99 added a boolean datatype. In Computer science, the Boolean datatype, sometimes called the logical datatype, is a Primitive datatype having one of two values There are also derived types including arrays, pointers, records (struct), and untagged unions (union). In Computer science an array is a Data structure consisting of a group of elements that are accessed by indexing. This article is about the data structure and the type In Computer science, a record type is a type whose values are records, i In Computer science, a union is a Data structure that stores one of several types of data at a single location

C is often used in low-level systems programming where escapes from the type system may be necessary. The compiler attempts to ensure type correctness of most expressions, but the programmer can override the checks in various ways, either by using a type cast to explicitly convert a value from one type to another, or by using pointers or unions to reinterpret the underlying bits of a value in some other way. In Computer science, type conversion or typecasting refers to changing an entity of one Data type into another

Pointers

C supports the use of pointers, a very simple type of reference that records, in effect, the address or location of an object or function in memory. In Computer science, a reference is an object containing information which refers to data stored elsewhere as opposed to containing the data itself Pointers can be dereferenced to access data stored at the address pointed to, or to invoke a pointed-to function. Pointers can be manipulated using assignment and also pointer arithmetic. The run-time representation of a pointer value is typically a raw memory address (perhaps augmented by an offset-within-word field), but since a pointer's type includes the type of the thing pointed to, expressions including pointers can be type-checked at compile time. Pointer arithmetic is automatically scaled by the size of the pointed-to data type. (See Array-pointer interchangeability below. ) Pointers are used for many different purposes in C. Text strings are commonly manipulated using pointers into arrays of characters. In Computer programming and some branches of Mathematics, a string is an ordered Sequence of Symbols. Dynamic memory allocation, which is described below, is performed using pointers. In Computer science, dynamic memory allocation is the allocation of memory storage for use in a Computer program during the Runtime of that program Many data types, such as trees, are commonly implemented as dynamically allocated struct objects linked together using pointers. In Computer science, a tree is a widely-used Data structure that emulates a Tree structure with a set of linked nodes Pointers to functions are useful for callbacks from event handlers. In Computer programming, a callback is Executable code that is passed as an argument to other code

A null pointer is a pointer value that points to no valid location (it is often represented by address zero). Dereferencing a null pointer is therefore meaningless, typically resulting in a run-time error. Null pointers are useful for indicating special cases such as no next pointer in the final node of a linked list, or as an error indication from functions returning pointers. In Computer science, a linked list is one of the fundamental Data structures and can be used to implement other data structures

Void pointers (void *) point to objects of unknown type, and can therefore be used as "generic" data pointers. Since the size and type of the pointed-to object is not known, void pointers cannot be dereferenced, nor is pointer arithmetic on them allowed, although they can easily be (and in many contexts implicitly are) converted to and from any other object pointer type.

Arrays

Array types in C are always one-dimensional and, traditionally, of a fixed, static size specified at compile time. In Computer science an array is a Data structure consisting of a group of elements that are accessed by indexing. (The more recent C99 standard also allows a form of variable-length arrays. ) However, it is also possible to allocate a block of memory (of arbitrary size) at run-time, using the standard library's malloc function, and treat it as an array. C's unification of arrays and pointers (see below) means that true arrays and these dynamically-allocated, simulated arrays are virtually interchangeable. Since arrays are always accessed (in effect) via pointers, array accesses are typically not checked against the underlying array size, although the compiler may provide bounds checking as an option. Array bounds violations are therefore possible and rather common in carelessly written code (see the "Criticism" article), and can lead to various repercussions: illegal memory accesses, corruption of data, buffer overrun, run-time exceptions, etc. tags please moot on the talk page first! --> In Computing, C is a general-purpose cross-platform block structured

C does not have a special provision for declaring multidimensional arrays, but rather relies on recursion within the type system to declare arrays of arrays, which effectively accomplishes the same thing. The index values of the resulting "multidimensional array" can be thought of as increasing in row-major order. In computing row-major order and column-major order describe methods for storing multidimensional arrays in linear memory

Array-pointer interchangeability

A distinctive (but potentially confusing) feature of C is its treatment of arrays and pointers. The array-subscript notation x[i] can also be used when x is a pointer; the interpretation (using pointer arithmetic) is to access the (i+1)th of several adjacent data objects pointed to by x, counting the object that x points to (which is x[0]) as the first element of the array.

Formally, x[i] is equivalent to *(x + i). Since the type of the pointer involved is known to the compiler at compile time, the address that x + i points to is not the address pointed to by x incremented by i bytes, but rather incremented by i multiplied by the size of an element that x points to. The size of these elements can be determined with the operator sizeof by applying it to any dereferenced element of x, as in n = sizeof *x or n = sizeof x[0]. In the programming languages C and C++, the Unary operator ' sizeof' is used to calculate the sizes of datatypes.

Furthermore, in most expression contexts (a notable exception is sizeof array), the name of an array is automatically converted to a pointer to the array's first element; this implies that an array is never copied as a whole when named as an argument to a function, but rather only the address of its first element is passed. Therefore, although C's function calls use pass-by-value semantics, arrays are in effect passed by reference. In Computer science, an evaluation strategy is a set of (usually deterministic rules for determining the evaluation of expressions in a Programming language In Computer science, a reference is an object containing information which refers to data stored elsewhere as opposed to containing the data itself

The number of elements in a declared array a can be determined as sizeof a / sizeof a[0].

An interesting demonstration of the interchangeability of pointers and arrays is shown below. The four assignments are equivalent and each is valid C code. Note how the last line contains the strange code i[x] = 1;, which has the index variable i apparently interchanged with the array variable x. This last line might be found in obfuscated C code. The International Obfuscated C Code Contest (abbreviated IOCCC) is a Programming contest for the most creatively obfuscated C Code 

/* x designates an array */x[i] = 1;*(x + i) = 1;*(i + x) = 1;i[x] = 1; /* strange, but correct: i[x] is equivalent to *(i + x) */

However, there is a distinction to be made between arrays and pointer variables. Even though the name of an array is in most expression contexts converted to a pointer (to its first element), this pointer does not itself occupy any storage. Consequently, you cannot change what an array "points to", and it is impossible to assign to an array. (Arrays may however be copied using the memcpy function, for example. )

Memory management

One of the most important functions of a programming language is to provide facilities for managing memory and the objects that are stored in memory. C provides three distinct ways to allocate memory for objects:

These three approaches are appropriate in different situations and have various tradeoffs. Static variable Static memory allocation refers to the process of allocating memory at compile-time before the associated program is executed unlike Dynamic memory A variable (ˈvɛərɪəbl is an Attribute of a physical or an abstract System which may change its Value while it is under Observation. In the C programming language Variables declared within a block of code are by default automatic variables. In Computer science, a call stack is a dynamic stack data structure which stores information about the active Subroutines of a Computer program In Computer science, dynamic memory allocation is the allocation of memory storage for use in a Computer program during the Runtime of that program In Computing, malloc is a Subroutine provided in the C and C++ programming language 's standard libraries for performing In Computer science, dynamic memory allocation is the allocation of memory storage for use in a Computer program during the Runtime of that program In Computing, malloc is a Subroutine provided in the C and C++ programming language 's standard libraries for performing For example, static memory allocation has no allocation overhead, automatic allocation may involve a small amount of overhead, and dynamic memory allocation can potentially have a great deal of overhead for both allocation and deallocation. On the other hand, stack space is typically much more limited and transient than either static memory or heap space, and dynamic memory allocation allows allocation of objects whose size is known only at run-time. Most C programs make extensive use of all three.

Where possible, automatic or static allocation is usually preferred because the storage is managed by the compiler, freeing the programmer of the potentially error-prone chore of manually allocating and releasing storage. However, many data structures can grow in size at runtime, and since static allocations (and automatic allocations in C89 and C90) must have a fixed size at compile-time, there are many situations in which dynamic allocation must be used. Prior to the C99 standard, variable-sized arrays were a common example of this (see "malloc" for an example of dynamically allocated arrays). In Computing, malloc is a Subroutine provided in the C and C++ programming language 's standard libraries for performing

Libraries

The C programming language uses libraries as its primary method of extension. In Computer science, a library is a collection of Subroutines used to develop Software. In C, a library is a set of functions contained within a single "archive" file. Each library typically has a header file, which contains the prototypes of the functions contained within the library that may be used by a program, and declarations of special data types and macro symbols used with these functions. In Computer programming, particularly in the C and C++ programming languages a header file or include file is a file, usually in In order for a program to use a library, it must include the library's header file, and the library must be linked with the program, which in many cases requires compiler flags (e. In computer Command line interfaces a command line argument is an argument sent to a program being called g. , -lm, shorthand for "math library").

The most common C library is the C standard library, which is specified by the ISO and ANSI C standards and comes with every C implementation. The C standard library (also known as libc) is a now-standardized collection of Header files and library routines used to implement common operations such tags please moot on the talk page first! --> In Computing, C is a general-purpose cross-platform block structured ("Freestanding" [embedded] C implementations may provide only a subset of the standard library. ) This library supports stream input and output, memory allocation, mathematics, character strings, and time values.

Another common set of C library functions are those used by applications specifically targeted for Unix and Unix-like systems, especially functions which provide an interface to the kernel. Unix (officially trademarked as UNIX, sometimes also written as Unix with Small caps) is a computer A Unix-like (sometimes shortened to *nix) Operating system is one that behaves in a manner similar to a Unix system while not necessarily conforming In Computer science, the kernel is the central component of most computer Operating systems (OS These functions are detailed in various standards such as POSIX and the Single UNIX Specification. POSIX (ˈpɒzɪks or "Portable Operating System Interface" is the collective name of a family of related standards specified by the IEEE to define The Single UNIX Specification ( SUS) is the collective name of a family of standards for Computer Operating systems to qualify for the name " Unix

Since many programs have been written in C, there are a wide variety of other libraries available. Libraries are often written in C because C compilers generate efficient object code; programmers then create interfaces to the library so that the routines can be used from higher-level languages like Java, Perl, and Python. In Computer science, object code, or an object file, is the representation of code that a Compiler or Assembler generates by processing NOTES FOR EDITORS "Perl" is not an acronym (read the "Name" section below Python is a general-purpose High-level programming language. Its design philosophy emphasizes programmer productivity and code readability

Criticism

Main article: Criticism of the C programming language

Despite its popularity, C has been widely criticized. Such criticisms fall into two broad classes: desirable operations that are too hard to achieve using unadorned C, and undesirable operations that are too easy to accidentally invoke while using C. Putting this another way, the safe, effective use of C requires more programmer skill, experience, effort, and attention to detail than is required for some other programming languages.

Tools for mitigating problems with C

Tools have been created to help C programmers avoid some of the problems inherent in the language.

Automated source code checking and auditing are beneficial in any language, and for C many such tools exist, such as Lint. In Computer programming, lint was the name originally given to a particular program that flagged suspicious and non-portable constructs (likely to be bugs in C language A common practice is to use Lint to detect questionable code when a program is first written. Once a program passes Lint, it is then compiled using the C compiler.

There are also compilers, libraries and operating system level mechanisms for performing array bounds checking, buffer overflow detection, serialization and automatic garbage collection, that are not a standard part of C. In Computer security and programming, a buffer overflow, or buffer overrun, is an anomalous condition where a process attempts to In Computer science, in the context of data storage and transmission serialization is the process of saving an object onto a storage medium (such as a In Computer science, garbage collection ( GC) is a form of automatic Memory management.

Cproto is a program that will read a C source file and output prototypes of all the functions within the source file. This program can be used in conjunction with the make command to create new files containing prototypes each time the source file has been changed. In Software development, make is a utility for automatically building executable programs from Source code. These prototype files can be included by the original source file (e. g. , as "filename. p"), which reduces the problems of keeping function definitions and source files in agreement.

It should be recognized that these tools are not a panacea. Because of C's flexibility, some types of errors involving misuse of variadic functions, out-of-bounds array indexing, and incorrect memory management cannot be detected on some architectures without incurring a significant performance penalty. However, some common cases can be recognized and accounted for.

Related languages

When object-oriented languages became popular, C++ and Objective-C were two different extensions of C that provided object-oriented capabilities. C++ (" C Plus Plus " ˌsiːˌplʌsˈplʌs is a general-purpose Programming language. Objective-C is a reflective, object-oriented Programming language which adds Smalltalk -style messaging to C. Both languages were originally implemented as preprocessors -- source code was translated into C, and then compiled with a C compiler.

C++

Main article: C++

Bjarne Stroustrup devised the C++ programming language as one approach to providing object-oriented functionality with C-like syntax. C++ (" C Plus Plus " ˌsiːˌplʌsˈplʌs is a general-purpose Programming language. Bjarne Stroustrup (/'bjɑːnə 'sdʁʌʊ̯ˀsdʁɔb/ born December 30, 1950 in Aarhus C++ adds greater typing strength, scoping and other tools useful in object-oriented programming and permits generic programming via templates. Generic programming is a style of Computer programming in which algorithms are written in terms of to-be-specified-later types that are then instantiated Nearly a superset of C, C++ now supports most of C, with a few exceptions (see Compatibility of C and C++ for an exhaustive list of differences). The C and C++ Programming languages are closely related C++ grew out of C and is mostly a superset of the latter

D

Main article: D (programming language)

Unlike C++, which maintains nearly complete backwards compatibility with C, D makes a clean break with C while maintaining the same general syntax. The D programming language, also known simply as D, is an object-oriented, imperative, multiparadigm System programming language C++ (" C Plus Plus " ˌsiːˌplʌsˈplʌs is a general-purpose Programming language. It abandons a number of features of C which Walter Bright (the designer of D) considered undesirable, including the C preprocessor and trigraphs. Walter Bright is a Computer programmer known for being the designer of the D programming language. The C preprocessor ( cpp) is the Preprocessor for the C programming language. In the C family of Programming languages a trigraph is a sequence of three characters, the first two of which are both Question marks that represents Some, but not all, of D's extensions to C overlap with those of C++.

Objective-C

Main article: Objective-C

Objective-C was originally a very "thin" layer on top of, and remains a strict superset of, C that permits object-oriented programming using a hybrid dynamic/static typing paradigm. Objective-C is a reflective, object-oriented Programming language which adds Smalltalk -style messaging to C. Objective-C derives its syntax from both C and Smalltalk: syntax that involves preprocessing, expressions, function declarations and function calls is inherited from C, while the syntax for object-oriented features was originally taken from Smalltalk. Smalltalk is an object-oriented, dynamically typed, reflective programming language.

Other influences

C has directly or indirectly influenced many later languages such as Java, C#, Perl, PHP, JavaScript, LPC, and Unix's C Shell. C# (pronounced C Sharp is a Multi-paradigm NOTES FOR EDITORS "Perl" is not an acronym (read the "Name" section below PHP is a computer Scripting language. Originally designed for producing Dynamic web pages it has evolved to include a Command line interface capability JavaScript is a Scripting language most often used for Client-side web development The LPC programming language is an Object-oriented Programming language derived from C and developed originally by Lars Pensjö to facilitate The C shell ( csh) is a Unix shell developed by Bill Joy for the BSD Unix system The most pervasive influence has been syntactical: all of the languages mentioned combine the statement and (more or less recognizably) expression syntax of C with type systems, data models and/or large-scale program structures that differ from those of C, sometimes radically.

See also

References

  1. ^ Dennis M. ANSI C is the standard published by the American National Standards Institute (ANSI for the C programming language. A compiler is a Computer program (or set of programs that translates text written in a computer language (the source language) into another The C preprocessor ( cpp) is the Preprocessor for the C programming language. The C standard library (also known as libc) is a now-standardized collection of Header files and library routines used to implement common operations such In computing a C string is a character sequence stored as a one-dimensional character Array and terminated with a Null character ('\0' The Syntax of the C programming language is a set of rules that specifies whether the sequence of characters in a file is conforming C Source code. The C programming language has an extensive system for declaring variables of different types. Programming languages are used for controlling the behavior of a machine (often a Computer) C++ (" C Plus Plus " ˌsiːˌplʌsˈplʌs is a general-purpose Programming language. Objective-C is a reflective, object-oriented Programming language which adds Smalltalk -style messaging to C. BitC is a Programming language currently being developed by researchers at the Johns Hopkins University and The EROS Group LLC as part of the Coyotos The D programming language, also known simply as D, is an object-oriented, imperative, multiparadigm System programming language The GNU Compiler Collection (usually shortened to GCC) is a set of Compilers produced for various Programming languages by the GNU Project Impulse C is a subset of the C programming language combined with a C-compatible Function library supporting Parallel programming, in particular for The International Obfuscated C Code Contest (abbreviated IOCCC) is a Programming contest for the most creatively obfuscated C Code This page is intended to list all current compilers compiler generators interpreters translators etc This is a list of operators in the C++ and C programming languages. A programming tool or software development tool is a program or application that Software developers use to create debug maintain or otherwise Cygwin (ˈsɪɡwɪn is a collection of tools originally developed by Cygnus Solutions to provide in Microsoft Windows a command line and programming interface familiar DJGPP (DJ's GNU Programming Platform is a 32-bit C / C++ / ObjC / ObjC++ / Ada / Fortran development suite for 386 The GNU Compiler Collection (usually shortened to GCC) is a set of Compilers produced for various Programming languages by the GNU Project LCC ("Local C Compiler" or "Little C Compiler" is a small free Retargetable compiler program for the ANSI C programming language In Software development, make is a utility for automatically building executable programs from Source code. In Computer programming, lint was the name originally given to a particular program that flagged suspicious and non-portable constructs (likely to be bugs in C language In Computing, Small-C is both a subset of the C programming language, suitable for resource-limited Microcomputers and Embedded systems and an C-- is a C -like Programming language. Its creators Functional programming researchers Simon Peyton Jones and Norman Ramsey, Pelles C is a lightweight Freeware Integrated development environment for Windows and Pocket PC programming in the C language built and maintained The computer Programming languages C and Pascal are often compared to each other sometimes heatedly probably because the languages have similar times of origin A Java Virtual Machine ( JVM) is a set of computer software programs and data structures which use a Virtual machine The Tiny C Compiler (aka TCC tCc or TinyCC is an X86 C language compiler created by Fabrice Bellard. Ritchie (Jan 1993). The Development of the C Language. Retrieved on Jan 1, 2008.  “The scheme of type composition adopted by C owes considerable debt to Algol 68, although it did not, perhaps, emerge in a form that Algol's adherents would approve of. ”
  2. ^ C was used to rewrite an early version of Unix that had been written in assembler. Stewart, Bill (2000-01-07). 2000 ( MM) was a Leap year that started on Saturday of the Common Era, in accordance with the Gregorian calendar. Events 1325 - Alfonso IV becomes King of Portugal. 1558 - France takes Calais, the last continental History of the C Programming Language. Living Internet. Retrieved on 2006-10-31. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 445 BC – Ezra reads the Book of the Law to the Israelites in Jerusalem (see Nehemiah 91 NLTse
  3. ^ Patricia K. Lawlis, c. j. kemp systems, inc. (1997). Guidelines for Choosing a Computer Language: Support for the Visionary Organization. Ada Information Clearinghouse. Retrieved on 2006-07-18. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 390 BC - Roman - Gaulish Wars Battle of the Allia - a Roman army is defeated by raiding Gauls,
  4. ^ Choosing the right programming language. Wikibooks (2006). Retrieved on 2006-07-18. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 390 BC - Roman - Gaulish Wars Battle of the Allia - a Roman army is defeated by raiding Gauls,
  5. ^ See Generational list of programming languages
  6. ^ Status of C99 features in GCC. Here a genealogy of Programming languages is shown Languages are categorized under the ancestor language with the strongest influence Free Software Foundation, Inc. (2007-11-22). Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 498 - Kofi Aseidu- After the death of Anastasius II, Symmachus is elected Pope in the Lateran Retrieved on 2008-01-09. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 475 - Byzantine Emperor Zeno is forced to flee his capital at Constantinople.
  7. ^ Sun Studio 12: C Compiler 5.9 Readme. Sun Microsystems, Inc. (2007-05-31). Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 1279 BC - Rameses II (The Great (19th dynasty becomes pharaoh of Ancient Egypt. Retrieved on 2008-01-09. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 475 - Byzantine Emperor Zeno is forced to flee his capital at Constantinople.
  8. ^ For C89, a diagnostic message is not required, but often one will be issued anyway.
  9. ^ The main function actually has two arguments, int argc and char *argv[], respectively, which can be used to handle command line arguments. In computer Command line interfaces a command line argument is an argument sent to a program being called The C standard requires that both forms of main be supported, which is special treatment not afforded any other function.

Further information

External links

History

Tutorials

What's in a type?, Floating point and derived types, Implementation details and Portability and pitfalls

Resources

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