1.3. Data Types

Data types in c 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.

The types in C can be classified as follows,

• Basic Types are arithmetic types and are further classified into: (a) integer types and (b) floating-point types.

• Enumerated types are again arithmetic types and they are used to define variables that can only assign certain discrete integer values throughout the program.

• The type void indicates that no value is available.

• Derived types 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 collectively as the aggregate types. The type of a function specifies the type of the function’s return value. We will see the basic types in the following subsections, where as some of the other types will be covered in the upcoming chapters.

1.3.1. Integer Types

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

Table 1.1 Integer Data Types in C Language

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

Warning

The storage size of some of the basic types can be different based on the machine.

1.3.2. Floating-Point Types

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

Table 1.2 Floating-Point Data Types in C Language

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