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C Variables





Variables In C, variable is a data name given to a data value stored in the memory and can vary at the time of execution. Name of the variable should be meaningful and in C there are some rules are defined for naming variables and rules to declare C Variables is that alphabets, digits and underscore, begins with the alphabets or underscores (_) and digits (0-9) and keyword cannot be used as a keyword. Here eitworld.com provides the learning tutorial of C variable with examples.

  • A variable is a data name given to a data value stored in the memory.
  • The value of variable can vary at the time of execution.
  • Name of the variable should be meaningful and in C there are some rules are defined for naming variables which are as follows:

Rules for naming Variable

  • Variable name may contain letters, digits and underscore (_) character.
  • The variable name can begin with the letters as well as with underscore (_) character.
  • A variable name should not start with digit.
  • A variable name cannot contain punctuation characters like (@,#,$,%,^,&,* etc)
  • A variable name cannot be a keyword.
  • The variable names may be a combination of uppercase and lowercase characters. For example name and naME are not the same.
45, -16, +56, 67 etc.

Variable Declaration in C

    • Declaration of a variable is necessary before using it into the program.
    • A variable is declared using a data type and a meaningful variable name. The basic syntax of variable declaration is as follows:
Data_type variable_name;
    • A variable can be of any data type like int, float, double and char etc.
    • Here are some examples of variable declaration:
int age;

float area;

char m;

int a,b,c;/*More than one variable of same type can be declare in single statement.*/

Initializing Variable

    • Variable can be initialized using the assignment operator ‘=’.
    • Variable declaration and initialization can also done in same line.
    • The basic syntax to initialize a variable is as follows:
variable_name=data_value;

—-OR—–

Data_type variable_name=data_value;

    • Some examples of declaring constant in C++ are given here:
const int a=10; const float b=10.34; const char c=’a’;
    • Here is an example of variable initialization:
int x;

x=3;

—-OR—-

int x=3;

Here is an example of using variable in C program:


#include<stdio.h>

int main()

{

int a;/*Variable declaration*/

a=5;/*Variable initialization*/

printf("nvalue of a is:%d",a);

return 0;

}

  • The output of the above program is as follows:
value of a is:5


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