Constants with iota for Enumerated Values

Snippet

Constants with iota for Enumerated Values

The `iota` keyword generates consecutive untyped integer constants. In the first block, it creates color codes (1, 2, 3). In the second block, `1 << iota` creates bit flags (1, 2, 4). The underscore `_` skips the zero value.

snippet.go
go
package main
 
import "fmt"
 
const (
    _ = iota
    Red int = iota
    Green
    Blue
)
 
const (
    Flag1 uint = 1 << iota
    Flag2
    Flag3
)
 
func main() {
    fmt.Printf("Colors: Red=%d, Green=%d, Blue=%d\n", Red, Green, Blue)
    fmt.Printf("Flags: Flag1=%d, Flag2=%d, Flag3=%d\n", Flag1, Flag2, Flag3)
}

Breakdown

const ( _ = iota

Underscore discards iota=0, starting enumeration at 1

Red int = iota

First named constant, iota=1, explicit type int

Green

Same type as Red, iota increments to 2 automatically

Flag1 uint = 1 << iota

Bit shift creates powers of 2: 1<<1 = 1

Flag2

iota=2, so 1<<2 = 2

Flag3

iota=3, so 1<<3 = 4

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Constants with iota for Enumerated Values

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