Go Pointers Explained Simply

• go
• pointers

Published on 2025-06-23

In Go, pointers let you refer to the memory address of a variable instead of the value directly. This is useful when you want to modify a variable inside a function or avoid copying large data structures like structs.

Key Concepts

Think in Analogies

• & is like asking: “What is the address of this house?”
• * is like saying: “Go to this address and see what’s inside.”

Basic Pointer Example

package main

import "fmt"

func main() {
    x := 10
    p := &x // p holds the address of x

    fmt.Println("x =", x)      // Output: 10
    fmt.Println("p =", p)      // Output: memory address (e.g., 0xc000018030)
    fmt.Println("*p =", *p)    // Output: 10 (value at address)

    *p = 20 // change the value at the memory address
    fmt.Println("x =", x)      // Output: 20
}

Modifying Values with Functions

You can pass a pointer to a function to allow it to modify the original value.

func modify(val *int) {
    *val = *val + 5 // modify the value at the pointer
}

func main() {
    x := 10
    modify(&x)      // pass the address of x
    fmt.Println(x)  // Output: 15
}

Summary

• &x → get the pointer (memory address) of x
• *p → access or modify the value at pointer p
• *T → define a pointer to type T (e.g., *int for pointer to an int)