C language Tutorial with programming approach for beginners and professionals, helps you to understand the C language tutorial easily. Our C tutorial explains each or every topic with example.

The C programing language is a procedural and general- purpose language that rovides low-level access to System memory is knows as C programming language.

Variable in C

A variable is a name of the memory location. It is use to store data. Its value can be change, and it can be reused many time is knows as Variable in C.


  • type variable_list;  

Rules for defining variables

  1. A variable can have alphabets, underscore or digits.
  2. A variable name can start with the alphabet, and underscore only.
  3. It can not start with a digit.
  4. No whitespace is allow within the variable name.
  5. A variable name must not be any reserve word or keyword.

Types of Variables in C

There are some important types of variables in c

  • local variable
    • Declare inside the function
  • global variable
    • Declare outside the function
  • static variable
    • Declare with the static keyword
  • automatic variable
    • Declare inside the block, are automatic variables by default
  • external variable

Simple example of Variables Declaration in C

Input value

#include <stdio.h>
extern int a, b;
extern int c;
extern float f;

int main () {

   int a, b;
   int c;
   float f;

   a = 45;
   b = 25;
   c = a + b;
   printf("value of c : %d \n", c);

   f = 72.0/3.0;
   printf("value of f : %f \n", f);
   return 0;

Output value

Output value


A data type specifies the type of data that a variable can store just like as integer, floating, character, etc. is knows as DataTypes in C programming language.


Datatypes of C programming Language

Basic Data Type

  • int
  • char
  • float
  • double
Data TypesMemory Size Range
char1 byte−128 to 127
short2 byte−32,768 to 32,767
int2 byte−32,768 to 32,767
short int2 byte−32,768 to 32,767
long int4 byte-2,147,483,648 to 2,147,483,647
float4 byte
double8 byte
long double10 byte

Derived Data Type

  • array
  • pointer
  • structure
  • union

Enumeration Data Type

  • enum


  • Void

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To know more about C Programming language please Wikipedia click here .

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