从另一个文件调用函数

Inside my directory /go/src/lodo I have two files, main.go and uniqueElement.

uniqueElement.go

package main

import "fmt"

func unique(a []int) {
    var value int

    for i:= range a {
        value = value ^ a[i]

    }
    fmt.Println(value)

}

main.go

package main

func main() {
    var a = []int{1, 4, 2, 1, 3, 4, 2}


    unique(a[0:])
}

I get an error

./main.go:7: undefined: unique

How can I correctly call unique from main?

You probably ran your code with go run main.go that only compiles and runs main.go try running go run main.go uniqueElement.go or building and running the binary generated

Change the name from unique to Unique.