Variables in C

A variable is a place holder for some value. All variables have some type associated with them, which expresses what 'type' of values they can be assigned. C offers a rich set of variables −

Character (char) variable in C

Character (char) variable holds a single character.

#include <stdio.h>

int main() {
   char c;        // char variable declaration
   c = 'A';       // defining a char variable
   
   printf("value of c is %c", c);
   
   return 0;
}

The output of the program should be −

value of c is A

Integer (int) variable in C

int variable holds singed integer value of single character.

#include <stdio.h>

int main() {
   int i;         // integer variable declaration
   i = 123;       // defining integer variable
   
   printf("value of i is %d", i);
   
   return 0;
}

The output of the program should be −

value of i is 123

Floating point (float) variable in C

float variable holds single precision floating point values.

#include <stdio.h>

int main() {
   float f;             // floating point variable declaration
   f = 12.001234;       // defining float variable
   
   printf("value of f is %f", f);
   
   return 0;
}

The output of the program should be −

value of f is 12.001234

Double precision(double) floating point variable in C

double variable holds double precision floating point values.

#include <stdio.h>

int main() {
   double d;            // double precision variable declaration
   d = 12.001234;       // defining double precision variable
   
   printf("value of d is %e", d);
   
   return 0;
}

The output of the program should be −

value of d is 1.200123e+01

Void (void) data type in C

void in C means "nothing" or "no-value". This is used either with pointer declarations or with function declarations.

// declares function which takes no arguments but returns an integer value
int status(void)  

// declares function which takes an integer value but returns nothing
void status(int)

// declares a pointer p which points to some unknown type
void * p