History of C Language.

C Language was  Invented  by  Dennis Ritchie at AT & T Bell Telephone Laboratories  USA in between 1969-1973, It is a basically High Level Programming Language and most popular language.

Basic AIM.

In today's world of computer programming, there are many high-level languages to choose from, such as Pascal,Basic But C stands apart from all these languages. This is due to its many desirable qualities. It is a robust language whose rich set of built-in functions and operators can be used to write any complex logic program. The C language compiler combines the capabilities of a low level language with the features of a high level language. Therefore the language is suitable for writing both system software as well as business packages & other software. You will many compilers available in the market written in C.

C is such a powerful, dominant and supple language, its use quickly spread beyond Bell Labs. In the late 70’s C began to replace widespread well-known languages of that time like PL/I, ALGOL etc. Programmers everywhere began using it to write all sorts of programs. Soon, however, different organizations began applying their own versions of C with a subtle difference. This posed a serious problem for system developers.

Basic Features.

• Program written in c are very efficient and fast. This is due to its variety of data types and powerful operators. It is many time faster than BASIC. This helps developers in saving their valuable time.
• C is a powerful and flexible language which helps system developers to deliver various complex tasks with ease. C is used for diverse projects as operating systems, word processors, graphics, spreadsheets, and even compilers for other languages.
• C is popular among professional programmers for programming, as a result, a wide variety of C compilers and helpful accessories are available.
• C is highly portable language. This means that a C program written for one computer system (an IBM PC, for example) can be run on another system (a DEC VAX system, perhaps) with little or no modification. Portability is enhanced by the ANSI standard for C, the set of rules for C compilers.
• C’s another striking feature is its ability to extend itself. A C program is basically a collection of various function supported by C library (also known as header files). We can also add our own functions to the C library. These functions can be reused in other applications or programs by passing pieces of information to the functions, you can create useful, reusable code.
• Writing C program with user-defined functions makes program more simple and easy to understand. Breaking a problem in terms of functions makes program debugging, maintenance and testing easier.

• Improvability. It made Unix easy to customize and improve by any programmer that could learn the high-level C programming language. Many did learn C, and went on to experiment with modifications to the operating system, producing many useful new extensions and enhancements. 

Why C?

C is a powerful, flexible language that provides fast program execution and imposes few constraints on the programmer. It allows low level access to information and commands while still retaining the portability and syntax of a high level language. These qualities make it a useful language for both systems programming and general purpose programs.

C's power and fast program execution come from it's ability to access low level commands, similar to assembly language, but with high level syntax. It's flexibility comes from the many ways the programmer has to accomplish the same tasks. C includes bitwise operators along with powerful pointer manipulation capabilities. C imposes few constraints on the programmer. The main area this shows up is in C's lack of type checking. This can be a powerful advantage to an experienced programmer but a dangerous disadvantage to a novice.

Another strong point of C is it's use of modularity. Sections of code can be stored in libraries for re-use in future programs. This concept of modularity also helps with C's portability and execution speed. The core C language leaves out many features included in the core of other languages. These functions are instead stored in the C Standard Library where they can be called on when needed. An example of this concept would be C's lack of built in I/O capabilities. I/O functions tend to slow down program execution and also be machine independent when running optimally. For these reasons, they are stored in a library separately from the C language and only included when necessary.

C was developed at Bell Laboratories in 1972 by Dennis Ritchie. Many of its principles and ideas were taken from the earlier language B and B's earlier ancestors BCPL and CPL. CPL ( Combined Programming Language ) was developed with the purpose of creating a language that was capable of both high level, machine independent programming and would still allow the programmer to control the behavior of individual bits of information. The one major drawback of CPL was that it was too large for use in many applications. In 1967, BCPL ( Basic CPL ) was created as a scaled down version of CPL while still retaining its basic features. In 1970, Ken Thompson, while working at Bell Labs, took this process further by developing the B language. B was a scaled down version of BCPL written specifically for use in systems programming. Finally in 1972, a co-worker of Ken Thompson, Dennis Ritchie, returned some of the generality found in BCPL to the B language in the process of developing the language we now know as C.

C's power and flexibility soon became apparent. Because of this, the Unix operating system which was originally written in assembly language, was almost immediately re-written in C ( only the assembly language code needed to "bootstrap" the C code was kept ). During the rest of the 1970's, C spread throughout many colleges and universities because of it's close ties to Unix and the availability of C compilers. Soon, many different organizations began using their own versions of C causing compatibility problems. In response to this in 1983, the American National Standards Institute ( ANSI ) formed a committee to establish a standard definition of C which became known as ANSI Standard C. Today C is in widespread use with a rich standard library of functions.

Uses of C

C's wide acceptance and efficiency is the reason why libraries of several other applications are often implemented in C. Some of the applications using C in its kernels are: ; ,

Uses of C are many in addition to Systems programming. Some of which are as follows :

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• Language compilers and interpreters
• Device drivers
• Telecom applications
• Network programming
• Digital Signal processing applications
• Database applications
• Text editors