How can I implement a void* in golang?

Question

I'm making a (non-binary) tree in Golang.

In Java, I'd use something like

 class Node{
   List <Object> data;
 }

Where data can be either a pointer to data or to a child node

In C or C++, I'd use a void*.

What type should I use in golang

side note: don't use void pointers :) – OrenIshShalom Nov 29 '21 at 09:56 — OrenIshShalom, Nov 29 '21 at 09:56

score 4 · Answer 1 · edited May 23 '17 at 11:58

4

There are no void pointers in Go. The way to handle this is by using the empty interface interface{} which is inherently implemented by all types. I asked a question about this awhile back which you can find here; Go equivalent of a void pointer in C

edited May 23 '17 at 11:58

Community

1
1

answered Jul 20 '16 at 23:12

evanmcdonnal

46,131
16
104
115

3

There's also unsafe.Pointer which is, well, less safe because it can be coerced into an arbitrary type. You're right that `interface{}` is more akin to `Object` though as it's simply a type that every other type "is". – Linear Jul 20 '16 at 23:15
Late to the party, but for the convenience of anyone else reading this, @LinearZoetrope sure, but you can make them safe with a [Type Assertion](https://stackoverflow.com/questions/14289256/cannot-convert-data-type-interface-to-type-string-need-type-assertion). – glowkeeper Apr 28 '20 at 18:57

score 4 · Accepted Answer · answered Jul 21 '16 at 00:17

I've never tried to solve this problem in any language, would this work in Go?

go play link edit after reading the duplicate question i see you're not asking about the implementation, enjoy anyway ♥︎

package main

import (
    "fmt"
)

type Node struct {
    List []*Node
    Data interface{}
}

func main() {
    trivial := Node{}

    leaf := Node{Data: 1}

    tree := Node{
        List: []*Node{
            &leaf,
            &leaf,
        },
    }
    out(trivial)
    out(leaf)
    out(tree)
}

func out(x interface{}) {
    fmt.Printf("%T:%+v\n", x, x)
}

// main.Node:{List:[] Data:<nil>}
// main.Node:{List:[] Data:1}
// main.Node:{List:[0xc82000e180 0xc82000e180] Data:<nil>}

How can I implement a void* in golang?

2 Answers2