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Golang nil Variable with Examples

Golang | nil Variable: Here, we are going to learn about the nil variable with examples.
Submitted by IncludeHelp, on October 13, 2021 [Last updated : March 15, 2023]

nil Variable

In the Go programming language, nil is a predeclared identifier representing the zero value for many types such as a pointer, channel, func, interface, map, or slice type.

Syntax

var nil Type

Parameter(s)

• None

Return Value

None

Example 1

// Golang program to demonstrate the
// example of nil variable

package main

import (
	"fmt"
)

func main() {
	// Declaring variables of different types
	// and assigning them with nil values
	a := (*struct{})(nil)
	b := []int(nil)
	c := map[int]bool(nil)
	d := chan string(nil)
	e := interface{}(nil)

	// Printing the types and values
	fmt.Printf("a: %T, %v\n", a, a)
	fmt.Printf("b: %T, %v\n", b, b)
	fmt.Printf("c: %T, %v\n", c, c)
	fmt.Printf("d: %T, %v\n", d, d)
	fmt.Printf("e: %T, %v\n", e, e)
}

Output

a: *struct {}, <nil>
b: []int, []
c: map[int]bool, map[]
d: chan string, <nil>
e: <nil>, <nil>

Example 2

// Golang program to demonstrate the
// example of nil variable

package main

import (
	"fmt"
)

func main() {
	// Comparing the type's
	// default values with nil
	fmt.Println(*new(*int) == nil)
	fmt.Println(*new([]int) == nil)
	fmt.Println(*new(map[int]bool) == nil)
	fmt.Println(*new(chan string) == nil)
	fmt.Println(*new(func()) == nil)
	fmt.Println(*new(interface{}) == nil)
}

Output

true
true
true
true
true
true

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