C Language

C is a structured programming language developed by Dennis Ritchie in 1973 at Bell Laboratories. It is one of the most popular computer languages today because of its structure, high-level abstraction, machine-independent feature. C language was developed with UNIX operating system, so it is strongly associated with UNIX, which is one of the most popular networks operating system in use today and the heart of internet data superhighway.

Characteristics of ‘C’ Language

  • Small size
  • Extensive use of function calls
  • Loose typing - unlike PASCAL
  • Structured language
  • Low level (BitWise) programming readily available
  • Pointer implementation - extensive use of pointers for memory, array, structures, and functions.

 Now, it had become a widely used professional language because of the following reasons.

  • It has high-level constructs.
  • It can handle low-level activities.
  • It produces efficient programs.
  • It can be compiled on a variety of computers.

Importance of C language

  • It is a robust language with a rich set of built-in functions and operators that can be used to write any complex program.
  • The C compiler combines the capabilities of an assembly language with features of a high-level language.
  • Programs written in C are efficient and fast. This is due to its variety of data type and powerful operators.
  • It is many time faster than BASIC.
  • C is highly portable this means that programs once were written can be run on another machine with little or no modification.
  • Another important feature of the C program is its ability to extend itself.
  • A-C program is basically a collection of functions that are supported by C library. We can also create our own function and add it to C library.
  • There are  32 keywords; several standard functions are available which can be used for developing a program.
  • C language is the most widely used language in operating systems and embedded system development today.


  • It is a reserved word, some meaning is already available to that word and that meaning will be recognized by the compiler.
  • In ‘C’ programming language total no. of keywords are ‘32’

E.g.:- If, else, while, const, break….

Keywords=32, operators=44, separators=14.


  • It is a special kind of symbol which performs a particular task
  • In the ‘C’ programming language total no. of operators are of “44”

E.g.: +,*,&,%.


By using separators, we can separate individual units ‘ called taken.

In ‘C’ programming language no. of separators are ‘14’.

E.g.:, . ; ‘“{space.


It is a fixed one never be changed during the execution of the program.

Constants are classified into two types. i.e.

  • Alphanumeric constants
  • Numeric constants

Alphanumeric constants

By using alphanumeric constants we can represent alphabets and numeric values. Alphanumeric constants are a combination of 52 alphabets, 44 operators, 14 separators,

0-9 numeric values and some spiral kind of symbols.

  • Under alphanumeric constants, we have only one type of data values.
  • In ‘C’ programming language total no of characters is 256.
  • When we are working with the characters, character representation must be within a single Quotation.
  • Within the single quotes, any content is called character constant.

E.g.: ‘A’, ‘d’, ‘@’,’*’,’5’

Numeric constants

By using numeric constants, we can represent value type data.

  • Numeric constants are classified into two type’si.e., INT, FLOAT.
  • Integer will represent the values without any functional parts.

E.g.:- 12, 16,-851,-47,-32765.

The foot will represent the values with functional parts.

Eg: 12.35, 16.89,-78.95….

Char, Int & Float are called basic data types (or) basic data.

Note: elements, because any data is a combination of these 3 types of constants only.

Predefined functions

The implementation part of the f’n is already available along with the compiler.

As a programmer, whenever we need to perform any specific task that simply called predefined f’n.

Eg: printf(), scanf(), clrscr(), getch(), sleep(), delay(),  atoi(),  ecut(),fcut(),get data(),settime(),exit()


The grammar of a specific programming language is called syntax.

The basic syntax of the ‘C’ Language is every statement should end with ‘;’

For an in-depth understanding of C Language click on

Storage classes in C

Recursion in C

Pointers in C

Arguments in C

Types of Functions in C

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