Go Programming

Data Types in Go

Data types specify the type of data that a valid Go variable can hold. In Go language, the type is divided into four categories which are as follows:

  1. Basic type: Numbers, strings, and booleans come under this category.
  2. Aggregate type: Array and structs come under this category.
  3. Reference type: Pointers, slices, maps, functions, and channels come under this category.
  4. Interface type

Here, we will discuss Basic Data Types in the Go language. The Basic Data Types are further categorized into three subcategories which are:

  • Numbers
  • Booleans
  • Strings

Numbers

In Go language, numbers are divided into three sub-categories that are:

  • Integers: In Go language, both signed and unsigned integers are available in four different sizes as shown in the below table. The signed int is represented by int and the unsigned integer is represented by uint.
Data Type Description

int8 8-bit signed integer
int16 16-bit signed integer
int32 32-bit signed integer
int64 64-bit signed integer
uint8 8-bit unsigned integer
uint16 16-bit unsigned integer
uint32 32-bit unsigned integer
uint64 64-bit unsigned integer
int Both in and uint contain same size, either 32 or 64 bit.
uint Both in and uint contain same size, either 32 or 64 bit.
rune It is a synonym of int32 and also represent Unicode code points.
byte It is a synonym of int8.
uintptr It is an unsigned integer type. Its width is not defined, but its can hold all the bits of a pointer value.

Example:

// Go program to illustrate
// the use of integers
package main
import "fmt"
       
func main() {
    
    // Using 8-bit unsigned int
    var X uint8 = 225
    fmt.Println(X, X-3)
    
    // Using 16-bit signed int
    var Y int16 = 32767
    fmt.Println(Y+2, Y-2)
}

Output:

225 222
-32767 32765
  • Floating-Point Numbers: In Go language, floating-point numbers are divided into two categories as shown in the below table:
Data Type Description
float32 32-bit IEEE 754 floating-point number
float64 64-bit IEEE 754 floating-point number

Example:

// Go program to illustrate
// the use of floating-point
// numbers
package main
import "fmt"
       
func main() {
    a := 20.45
    b := 34.89
    
    // Subtraction of two
    // floating-point number
    c := b-a
    
    // Display the result
    fmt.Printf("Result is: %f", c)
    
    // Display the type of c variable
    fmt.Printf("\nThe type of c is : %T", c) 
}

Output:

Result is: 14.440000
The type of c is : float64
  • Complex Numbers: The complex numbers are divided into two parts are shown in the below table. float32 and float64 are also part of these complex numbers. The in-built function creates a complex number from its imaginary and real part and in-built imaginary and real function extract those parts.
Data Type Description

complex64 Complex numbers which contain float32 as a real and imaginary component.
complex128 Complex numbers which contain float64 as a real and imaginary component.

Example:

// Go program to illustrate
// the use of complex numbers
package main
import "fmt"
func main() {
    
   var a complex128 = complex(6, 2)
   var b complex64 = complex(9, 2)
   fmt.Println(a)
   fmt.Println(b)
   
   // Display the type
  fmt.Printf("The type of a is %T and "+
            "the type of b is %T", a, b)
}

Output:

(6+2i)
(9+2i)
The type of a is complex128 and the type of b is complex64

Booleans

The boolean data type represents only one bit of information either true or false. The values of type boolean are not converted implicitly or explicitly to any other type.

Example:

// Go program to illustrate
// the use of booleans
package main
import "fmt"
func main() {
    
    // variables
   str1 := "GeeksforGeeks"
   str2:= "geeksForgeeks"
   str3:= "GeeksforGeeks"
   result1:= str1 == str2
   result2:= str1 == str3
   
   // Display the result
   fmt.Println( result1)
   fmt.Println( result2)
   
   // Display the type of
   // result1 and result2
   fmt.Printf("The type of result1 is %T and "+
                   "the type of result2 is %T",
                             result1, result2)
   
}

Output:

false
true
The type of result1 is bool and the type of result2 is bool

Strings

The string data type represents a sequence of Unicode code points. Or in other words, we can say a string is a sequence of immutable bytes, means once a string is created you cannot change that string. A string may contain arbitrary data, including bytes with zero value in the human-readable form.

Example:

// Go program to illustrate
// the use of strings
package main
import "fmt"
func main() {
    
    // str variable which stores strings
   str := "GeeksforGeeks"
   
   // Display the length of the string
   fmt.Printf("Length of the string is:%d",
                                  len(str))
   
   // Display the string
   fmt.Printf("\nString is: %s", str)
   
   // Display the type of str variable
   fmt.Printf("\nType of str is: %T", str)
}

Output:

Length of the string is:13
String is: GeeksforGeeks
Type of str is: string
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