Data Types in C

• Data types determine the type of data a variable can hold. Data types are the means to identify the type of data and associated operations of handling it.
• Example: if a variable 'x' is declared as 'int', the 'x' can hold only integer values.
• Data types are divided into three,
  1. The system defined data types
  2. Derived data types
  3. User-defined data types

The system defined data types

• System defined data types are the data types defined by the c compiler.
• System defined data types can be divided as
  1. Numeric-integers, float
  2. character-single characters, string characters

Derived data types

• These data types can be declared by the user by deriving the system-defined data type concepts.
• Examples: Arrays, pointers.
• Arrays: Collection of the same type of data referenced by a common name.
• pointers: A variable that can hold the address of a memory location. The declaration of the pointer should consist of data type, an * (asterisk) and the variable name.

User-defined data types

• These data types can be defined by the user.
• Three types:
  1. Structures
  2. Unions
  3. Enumerations

Datatype modifiers

• Type modifiers are the keyword used along with the basic data types to extend the range of data handled by the basic types.
• The type modifiers of C are
  1. signed
  2. unsigned
  3. long
  4. short

Data type	Memory
int	2
char	1
float	4
double	8
string	size of the char array
unsigned int	2
long unsigned	8
long	4