Data Types In C Language

In C language, data types refer to an extensive system used for declaring variables or functions of different types. The type of a variable determines how much space it occupies in storage and how the bit pattern stored is interpreted.

Different data types also have different ranges up to which they can store numbers. These ranges of data types may vary from compiler to compiler.

The types in C language can be classified as follows:

Types And Descriptions
Basic Types: They are arithmetic types and consists of the two types: (a) integer types and (b) floating-point types.
Enumerated types: They are again arithmetic types and they are used to define variables that can only be assigned certain discrete integer values throughout the program.
The type void: The type specifier void indicates that no value is available.
Derived types: They include (a) Pointer types, (b) Array types, (c) Structure types, (d) Union types and (e) Function types.

The array types and structure types are referred to collectively as the aggregate types. The type of a function specifies the type of the function’s return value. We will see basic types in the following section.

Integer Type

Following table gives you details about standard integer types with its storage sizes and value ranges:

TypeStorage SizeValue Range
Char1 byte-128 to 127 or 0 to 255
unsigned1 byte0 to 255
signed char1 byte-128 to 127
int2 or 4 bytes-32,768 to 32,767 or -2,147,483,648 to 2,147,483,647
unsigned int2 or 4 bytes0 to 65,535 or 0 to 4,294,967,295
short2 bytes-32,768 to 32,767
unsigned short2 bytes0 to 65,535
long2 bytes-2,147,483,648 to 2,147,483,647
unsigned long4 bytes0 to 4,294,967,295

To get the exact size of a data type or a variable on a particular platform, you can use the size of operator. The expressions sizeof(type) yields the storage size of the object or data type in bytes. Following is an example to get the size of int data type, char data type, float data type, double data type in your compiler.


int main()
int a;
char b;
float c;
double d;
printf(“Storage size for int data type:%d \n”,sizeof(a));
printf(“Storage size for char data type:%d \n”,sizeof(b));
printf(“Storage size for float data type:%d \n”,sizeof(c));
printf(“Storage size for double data type:%d\n”,sizeof(d));
return 0;


Storage size for int data type:4
Storage size for char data type:1
Storage size for float data type:4
Storage size for double data type:8

Floating-Point Types

Following table gives you details about standard floating-point data types with storage sizes and value ranges and their precision:

Type Storage Size Value Range Precision
float 4 byte -128 to 127 or 0 to 255 6 decimal places
double 8 byte 2.3E-308 to 1.7E+308 15 decimal places
long double 10 byte 3.4E-4932 to 1.1E+4932 19 decimal places
#include <stdio.h>
#include <float.h>
int main()
{ printf(“Storage size for float : %d \n”, sizeof(float));
printf(“Minimum float positive value: %E\n”, FLT_MIN );
printf(“Maximum float positive value: %E\n”, FLT_MAX );
printf(“Precision value: %d\n”, FLT_DIG ); return 0; }

Storage size for float : 4 
Minimum float positive value: 1.175494E-38 
Maximum float positive value: 3.402823E+38 
Precision value: 6

The void Data Type

  • Void is an empty data type that has no value.
  • This type of data type can be used in functions and pointers.
  • Please visit “Function” topic to know how to use void data type in function with simple call by value and call by reference example programs.

It is used in three kinds of situations:

Types And Description
Function returns as void There are various functions in C which do not return value or you can say they return void. A function with no return value has the return type as void. For example, void exit (int status);
Function arguments as void There are various functions in C which do not accept any parameter. A function with no parameter can accept as a void. For example, int rand(void);
Pointers to void A pointer of type void * represents the address of an object, but not its type. For example, a memory allocation function void *malloc( size_t size ); returns a pointer to void which can be casted to any data type.
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