2.1 C LANGUAGE - INTRODUCTION

C language is a structured programming language, was developed at Bell Laboratories in 1972 by Dennis Ritchie. C language features were derived from earlier language called “B” (Basic Combined Programming Language – BCPL). C language was invented for implementing UNIX operating system.

In 1978, Dennis Ritchie and Brian Kernighan published the first edition “The C Programming Language” and commonly known as K&R C. In 1983, the American National Standards Institute (ANSI) established a committee to provide a modern, comprehensive definition of C. The resulting definition, the ANSI standard, or “ANSI C”, was completed late 1988.

C Standards 

• C89/C90 standard – First standardized specification for C language was developed by American National Standards Institute in 1989. C89 and C90 standards refer to the same programming language.
• C99 standard – Next revision was published in 1999 that introduced new futures like advanced data types and other changes.

C11 and Embedded C 

• C11 standard adds new features to C and library like type generic macros, anonymous structures, improved Unicode support, atomic operations, multi-threading, and bounds-checked functions. It also makes some portions of the existing C99 library optional, and improves compatibility with C++.
• Embedded C includes features not available in normal C like fixed-point arithmetic, named address spaces, and basic I/O hardware addressing.
• Operating systems, C compiler and all UNIX application programs are written in C language.
• It is also called as procedure oriented programming language.
• C language is reliable, simple and easy to use.
• C has been coded in assembly language.

Features of C language 

Reliability Portability Flexibility Interactivity Modularity Efficiency and Effectiveness Uses of C language  C language is used for developing system applications that forms major portion of operating systems such as Windows, UNIX and Linux. Below are some examples of C being used: Database systems Graphics packages Word processors Spread sheets Operating system development Compilers and Assemblers Network drivers Interpreters

 Which level the C language belongs to?

S.no	High Level	Middle Level	Low Level
1	High level languages provides almost everything that the programmer might need to do as already built into the language	Middle level languages don’t provide all the built-in functions found in high level languages, but provides all building blocks that we need to produce the result we want	Low level languages provides nothing other than access to the machines basic instruction set
2	Examples: Java, Python	C, C++	Assembler