C - Language Overview

C – Language History

· The C programming language is a structure oriented programming language, developed at Bell Laboratories in 1972 by Dennis Ritchie

· C programming language features were derived from an 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 PROGRAMMING LANGUAGE STANDARDS:

· C89/C90 standard – First standardized specification for C language was developed by the 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 features like advanced data types and other changes.

C11 AND EMBEDDED C LANGUAGE:

· C11 standard adds new features to C programming language 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 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. The C language is reliable, simple and easy to use. C has been coded in assembly language.

FEATURES OF C PROGRAMMING LANGUAGE:

C language is one of the powerful language. Below are some of the features of C language.

· Reliability

· Portability

· Flexibility

· Interactivity

· Modularity

· Efficiency and Effectiveness

USES OF C PROGRAMMING LANGUAGE:

The C programming language is used for developing system applications that forms a 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

· Spreadsheets

· Operating system development

· Compilers and Assemblers

· Network drivers

· Interpreters

WHICH LEVEL IS C LANGUAGE BELONGING TO?

There are 3 levels of programming languages. They are,

1. MiddleLevellanguages:
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. Examples: C, C++

2. HighLevellanguages:
High level languages provide almost everything that the programmer might need to do as already built into the language. Example: Java, Python

3. LowLevellanguages:
Low level languages provides nothing other than access to the machines basic instruction set. Example: Assembler

C LANGUAGE IS A STRUCTURED LANGUAGE:

Structure oriented language:

· In this type of language, large programs are divided into small programs called functions

· Prime focus is on functions and procedures that operate on the data

· Data moves freely around the systems from one function to another

· Program structure follows “Top Down Approach”

· Examples: C, Pascal, ALGOL and Modula-2

Object oriented language:

· In this type of language, programs are divided into objects

· Prime focus is in the data that is being operated and not on the functions or procedures

· Data is hidden and cannot be accessed by external functions

· Program structure follows “Bottom UP Approach”

· Examples: C++, JAVA and C# (C sharp)

Non structure oriented language:

· There is no specific structure for programming this language. Examples: BASIC, COBOL, FORTRAN

KEY POINTS TO REMEMBER IN C LANGUAGE:

1. The C language is a structure oriented programming language developed by Dennis Ritchie.

2. The C language is belonging to middle level programming language.

3. Operating system programs such as Windows, Unix, Linux are written in C language.

4. C89/C90 and C99 are two standardized editions of C language.

5. C has been written in assembly language.