Pointers in Go

Go has pointers but no pointer arithmetic: they exist to share and to mutate.

type Counter struct {
    n int
}

func (c *Counter) Add(delta int) { c.n += delta }
func (c Counter) Value() int     { return c.n }

func pointers() (int, int, bool) {
    counter := Counter{}
    counter.Add(3) // Go takes the address for you
    byPointer := &counter
    byPointer.Add(4)

    fresh := new(int)
    *fresh = 7

    var nothing *Counter
    return counter.Value(), *fresh, nothing == nil
}

How it works

1. &x takes an address, *p reads through it.
2. new(T) allocates a zero T and returns its pointer.
3. A nil pointer dereference panics, so check when it can be nil.

Keywords and builtins used here

• bool
• func
• int
• new
• return
• struct
• type
• var

The run, in numbers

Lines

19

Characters to type

372

Tokens

102

Three-star pace

80 tpm

At the three-star pace of 80 tokens a minute, this run takes about 76 seconds.

Type this snippet

Step 5 of 5 in Variables & types, step 5 of 30 in Language basics.

← Previous Next →

Pointers in other languages

• C