Data types are declarations for variables. It specifies the type and size of data that a variable can store. Each data type requires different amounts of memory and has some specific operations which can be performed over it.

There are the following data types in C

1. Basic Data Type
2. Derived Data Type
3. Enumeration Data Type
4. Void Data Type

Basic Data Types:-

It is also known as Primary Data Type. They are arithmetic types (integer-based and floating-point based). The memory size of the basic data types may change according to 32 or 64-bit operating system.

We can use the sizeof() operator to check the size of a variable on a particular platform.

C program to find the sizes of each of C’s data types in our system:–

#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
int main( void )
{
  printf( "Size of C data types:\n\n"                                 );
  printf( "Type               Bytes\n\n"                             );
  printf( "--------------------------------\n");
  printf( "char                 %lu\n" , sizeof( char )               );
  printf( "unsigned char        %lu\n" , sizeof( unsigned char )      );
  printf( "short                %lu\n" , sizeof( short )              );
  printf( "int                  %lu\n" , sizeof( int )                );
  printf( "unsigned             %lu\n" , sizeof( unsigned )           );
  printf( "long                 %lu\n" , sizeof( long )               );
  printf( "unsigned long        %lu\n" , sizeof( unsigned long )      );
  printf( "long long            %lu\n" , sizeof( long long )          );
  printf( "int64_t              %lu\n" , sizeof( int64_t )            );
  printf( "unsigned long long   %lu\n" , sizeof( unsigned long long ) );
  printf( "float                %lu\n" , sizeof( float )              );
  printf( "double               %lu\n" , sizeof( double )             );
  printf( "long double          %lu\n" , sizeof( long double )        );
  printf( "\n" );
return 0;
}

int:- Integers are whole numbers that can have both zero, positive and negative values but no decimal values.

** The keyword unsigned uses to store all the value of the number and always positive or Zero.

int a = 5;

Char:- It is used for declaring character type variables and stores a single character.

char i = u;

float:- It is used to store decimal numbers with single precision.

Double:- It is used to store decimal numbers with double precision.

Void Data Type:-

It means nothing or no value available. If a function is not returning anything, its return type should be void.

** We cannot create variables of void data type.

Derived Data Types:-

Data types that are derived from fundamental data types are derived types.

Enumerated Data Types:-

It can only assign certain discrete integer values throughout the program.