Introduction

C is a general-purpose, high-level language that was originally developed by Dennis M. Ritchie to develop the UNIX operating system at Bell Labs. C was originally first implemented on the DEC PDP-11 computer in 1972.
In 1978, Brian Kernighan and Dennis Ritchie produced the first publicly available description of C, now known as the K&R standard.
The UNIX operating system, the C compiler, and essentially all UNIX applications programs have been written in C. The C has now become a widely used professional language for various reasons.

1.Easy to learn
2.Structured language
3.It produces efficient programs.
4.It can handle low-level activities.
5.It can be compiled on a variety of computer platforms.

Facts about

1.C was invented to write an operating system called UNIX.
2.C is a successor of B language which was introduced around 1970
3.The language was formalized in 1988 by the American National Standard Institute (ANSI).
4.The UNIX OS was totally written in C by 1973.
5.Today C is the most widely used and popular System Programming Language.
6.Most of the state-of-the-art softwares have been implemented using C.
7.Today's most popular Linux OS and RBDMS MySQL have been written in C.

Why to use C?

C was initially used for system development work, in particular the programs that make-up the operating system. C was adopted as a system development language because it produces code that runs nearly as fast as code written in assembly language. Some examples of the use of C might be:

• Operating Systems

• Language Compilers

• Assemblers

• Text Editors

• Print Spoolers

• Network Drivers

• Modern Programs

• Databases

• Language Interpreters

• Utilities

C Programs

A C program can vary from 3 lines to millions of lines and it should be written into one or more text files with extension ".c"; for example, hello.c. You can use "vi", "vim" or any other text editor to write your C program into a file.

This tutorial assumes that you know how to edit a text file and how to write source code inside a program file.