C language was developed in early 1970s by Dennis Ritchie at Bell Laboratories to implement the UNIX operating system on the PDP-11 manufactured by DEC (Digital Equipment Corporation). Programmed Data Processor (abbreviated PDP) was the name of a series of minicomputers made by Digital Equipment Corporation.

In the past, it was mainly used for writing system programs such as operating system, compilers, assemblers and utility programs. Today it is preferred by many programmers for writing all types of application programs as well such as: word processing programs, Spreadsheet programs, database management systems, educational programs, games etc.

It is highly structured language. C language program are easy to understand and follow. It has the ability to manipulate bits, bytes and addresses. It is sometimes called a mid-level language since it combines some feature of low level language (assembly) language and some of high level language. Therefore, it has advantages of both. It is low level in the sense that it can manipulate bits and works more like the computers And high level in the sense that its program structure is very similar to Pascal and Ada.

C language has a small set of reserved words and the basic data types are integer, floating point number and character. It does not have read and write statement like other languages for performing input/output operations. These operations are performed by means of functions provided in standard library. Some obscure abbreviations are also used in C. New features have been added, some modified and some obsolete ones deleted.

To ensure that C programs written on one system can be executed on another, international standard for the language have been formulated. In 1980s, American National standard Institute (ANSI) introduced the standard version of C language. The first standard for C was published by ANSI.

ANSI C refers to the family of successive standards published by the American National Standards Institute (ANSI) for the C programming language. Most software developers have adopted ANSI C for writing C compilers which made C more portable. If the programs are not portable then program written on one system cannot run on another and the programming efforts and the time spent on the old system would have been wasted.

Uses of C are many in addition to Systems programming. Some of which are as follows: Language compilers and interpreters Device drivers Telecom applications Network programming Digital Signal processing applications Database applications Text editors