Dereferencing a pointer

In this article, we explore how to dereference pointers in Go. Dereferencing a pointer means accessing the value stored in the memory address that the pointer holds.

Basic Syntax

To read and modify the value of the variable pointed to by a pointer, use the following syntax:

*<pointer_name>
*<pointer_name> = <new_value>

Example 1: Simple Dereferencing

Consider this example where we have a variable x holding a numeric value and a pointer ptr that stores the address of x:

x := 77
var ptr *int := &x

Here, the pointer ptr stores an address (e.g., 0x0301). When we dereference ptr and assign a new value, x is updated accordingly:

x := 77
var ptr *int = &x
*ptr = 100

Example 2: Practical Pointer Dereferencing in Go

This Go program demonstrates a practical application of pointer dereferencing using a string variable. Initially, the string variable s is set to "hello". We then create a pointer ps (using the shorthand operator) to store the address of s. By dereferencing ps, we update the value of s from "hello" to "world". The program prints the type and the updated value of s.

package main
import "fmt"

func main() {
    s := "hello"
    fmt.Printf("%T %v\n", s, s)
    ps := &s
    *ps = "world"
    fmt.Printf("%T %v\n", s, s)
}

When you run this program, the output will be:

>>> go run main.go
string hello
string world

That concludes our guide on dereferencing pointers in Go. To further enhance your skills, be sure to explore additional concepts in the Go Documentation.