Data Type in C

Data Types : ANSI C provides three types of data types which are as

   Primary (Built-in) Data Types :
     void, int, char, double and float.

   Derived Data Types :
    Array, References, and Pointers.

   User Defined Data Types :
   Structure, Union, and Enumeration.

   Primary(Built-in) Data Types :

Type	Size (bytes)	Format Specifier
int	at least 2, usually 4	%d
char	1	%c
float	4	%f
double	8	%lf
short int	2 usually	%hd
unsigned int	at least 2, usually 4	%u
long int	at least 4, usually 8	%li
long long int	at least 8	%lli
unsigned long int	at least 4	%lu
unsigned long long int	at least 8	%llu
signed char	1	%c
unsigned char	1	%c
long double	at least 10, usually 12 or 16	%Lf

Integer Types : The following table provides the details of standard integer types with their storage sizes and value ranges.

Type	Storage size	Value range
char	1 byte	-128 to 127 or 0 to 255
unsigned char	1 byte	0 to 255
signed char	1 byte	-128 to 127
int	2 or 4 bytes	-32,768 to 32,767 or -2,147,483,648 to 2,147,483,647
unsigned int	2 or 4 bytes	0 to 65,535 or 0 to 4,294,967,295
short	2 bytes	-32,768 to 32,767
unsigned short	2 bytes	0 to 65,535
long	8 bytes	-9223372036854775808 to 9223372036854775807
unsigned long	8 bytes	0 to 18446744073709551615

Floating-Point Types : The following table provide the details of standard floating-point types with storage sizes and value ranges and their precision. 

Type	Storage size	Value range	Precision
float	4 byte	1.2E-38 to 3.4E+38	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

The void Type : The void type specifies that no value is available. It is used in three kinds of situations.

S.No.	Types & Description
1	Function returns as void : There are various functions in C which do not return any 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);
2	Function arguments as void : There are various functions in C which do not accept any parameter. A function with no parameter can accept a void.  For example : int rand(void);
3	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 ); returns a pointer to void which can be casted to any data type.

Derived Data Types:

Data Type	Description
Arrays	Arrays are sequences of data items having homogeneous values. They have adjacent memory locations to store values.
References	Function pointers allow referencing functions with a particular signature.
Pointers	These are powerful C features which are used to access the memory and deal with their addresses.

 User defined Data types:

DataType	Description
Structure	It is a package of variables of different types under a single name. This is done to handle data efficiently. "struct" keyword is used to define a structure.
Union	These allow storing various data types in the same memory location. We can define a union with different members, but only a single member can contain a value at a given time. It is used for save memory."union" keyword is used to define a union.
Enum	Enumeration is a special data type that consists of integral constants, and each of them is assigned with a specific name. "enum" keyword is used to define the enumerated data type.