Go - Data Types

In the Go programming 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.

The types in Go can be classified as follows:

S.N.	Types and Description
1	Boolean Types They are boolean types and consists of the two predefined constants: (a) true (b) false
2	Numeric Types They are again arithmetic types and they represents a) integer types or b) floating point values throughout the program.
3	string types: A string type represents the set of string values. Its value is a sequence of bytes. Strings are immutable types that is once created, it is not possible to change the contents of a string. The predeclared string type is string.
4	Derived types: They include (a) Pointer types, (b) Array types, (c) Structure types, (d) Union types and (e) Function types f) Slice types g) Function types h) Interface types i) Map types j) Channel Types

The array types and structure types are referred to collectively as the aggregate types. The type of a function specifies the set of all functions with the same parameter and result types. We will see basic types in the following section, whereas, other types will be covered in the upcoming chapters.

Integer Types

The predefine architecture-independent integer types are:

S.N.	Types and Description
1	uint8 Unsigned 8-bit integers (0 to 255)
2	uint16 Unsigned 16-bit integers (0 to 65535)
3	uint32 Unsigned 32-bit integers (0 to 4294967295)
4	uint64 Unsigned 64-bit integers (0 to 18446744073709551615)
5	int8 Signed 8-bit integers (-128 to 127)
6	int16 Signed 16-bit integers (-32768 to 32767)
7	int32 Signed 32-bit integers (-2147483648 to 2147483647)
8	int64 Signed 64-bit integers (-9223372036854775808 to 9223372036854775807)

Floating Types

The predefine architecture-independent float types are:

S.N.	Types and Description
1	float32 IEEE-754 32-bit floating-point numbers
2	float64 IEEE-754 64-bit floating-point numbers
3	complex64 Complex numbers with float32 real and imaginary parts
4	complex128 Complex numbers with float64 real and imaginary parts

The value of an n-bit integer is n bits and is represented using two's complement arithmetic operations.

Other Numeric Types

There is also a set of numeric types with implementation-specific sizes:

S.N.	Types and Description
1	byte same as uint8
2	rune same as int32
3	uint 32 or 64 bits
4	int same size as uint
5	uintptr an unsigned integer to store the uninterpreted bits of a pointer value