Pointers in Go

Understand addresses, dereferencing, nil pointers, pointers with structs and methods, and when to pass pointers to functions.

Pointer Basics

A pointer holds the address of a value. Use `&` to take the address, and `*` to follow a pointer to the value.

1. Getting Address and Dereferencing

Use & to get address; *p to access the value.

Nil Pointers and new

The zero value of a pointer is `nil`. Use `new(T)` to allocate a `T` and get `*T`, or take the address of an existing variable.

1. Zero Value is nil

Uninitialized pointer variables are nil.

Pointers and Functions

Function parameters are passed by value. To let a function modify a variable, pass a pointer and change the value via `*p`.

1. Modifying a Value via Pointer

Compare passing by value vs passing a pointer.

Pointers to Structs

Pointers to structs are common: they avoid copying large structs and let functions modify fields directly.

1. Updating Struct Fields via Pointer

Pass *Struct to modify fields inside a function.

Methods and Automatic Dereferencing

When you have a `*T`, Go lets you write `p.Field` and `p.Method()` instead of `(*p).Field` and `(*p).Method()`. The compiler inserts one level of dereference or address-of where possible.

1. Automatic Dereference for Fields

Access struct fields directly on *T without writing (*p).Field.

2. Methods on Value and Pointer Receivers

Call methods with value or pointer receivers on both T and *T when the value is addressable.

Best Practices with Pointers

Use pointers when you need to modify a value in a function or avoid copying large structs. Check for nil before dereferencing.

1. Guidelines

Simple rules for everyday Go code.