Introduction to C Language


  • In computing, C is a general-purpose procedural computer programming language. It was originally made to use with UNIX operating system.
  • Although C was designed for developing system software, but it is also widely used for developing application software.
  • It is used in many different software platforms and computer architectures.
  • C has greatly influenced many other popular programming languages; most notably C++, which originally was as an extension to C.

History of C Language

  • Dennis Ritchie developed this language in 1972 in AT & T Bell Laboratories.
  • It was derived from B programming Language which was developed by Ken Thompson in 1969-70. B was the basis for C Language.
  • It was native Language of UNIX.
  • System programs under UNIX were designed in C.
  • The earlier version of C was known as K & R (Kernighan and Ritchie).

ANSI (American national standard institute) developed a standard version of C called ANSI C.

Advantages of C Language

System Programming: C provides a powerful approach for system programming. It was mainly designed to develop system software programs. Programmers can write complex software programs more easily than any other low level language.

Platform Independence: C is a machine independent language. It means that programs written in C language can be executed on any type of computer hardware with a little modification. For example, a C program written for Intel micro-processor can be executed on a machine that uses AMD micro-processor.

Small Language: C is a very small language. It requires limited space (only some KB’s) on computer’s hard disk. It has only, few reserve words. In spite of that, it is very powerful for developing different types of programs.

Fast Code Execution: The code written in C language executes very quickly. Minimum code execution time is the major cause of using C language for big system level software projects. Its compiler converts the source code into the object code in a very short period of time.

Flexible Codes: The programs written in C language are very flexible. A programmer can easily change codes. Procedures and functions help the programmers to utilize them for multiple purposes.

Structured Programming: C provides structured programming approach. In structured programming a program is divided into small units called modules. Each module consists of different instructions to perform a particular task.

Easy to Learn and Use: C is a very simple language. It is easy to learn and use. Instructions of C have very simple syntax. So, a programmer needs not necessary to have a detailed knowledge of computer architecture.

Source program

  • The program written in High Level Language is called source program.
  • The computer does not understand the source code.
  • The source code is converted into machine code and then it is directly executed on the computer.

Object Program

  • The machine language version that results from compiling the source is called object code. Compiler stores the object code on storage media for exhibition.
  • The computer understands the object code directly.