Stdle #61 · interfaces · 2026-08-06

What does this Go snippet output?

A past puzzle — fully playable. 4 attempts, hints on wrong guesses.

1package main
2 
3import "fmt"
4 
5type T struct{ N int }
6 
7func main() {
8	var i interface{} = T{5}
9	switch v := i.(type) {
10	case T:
11		fmt.Println(v.N)
12	default:
13		fmt.Println("?")
14	}
15}

Interfaces

What does this Go snippet output?

Answer & explanation