问如何从其他文件调用函数

EN

.
├── deck.go
└── main.go

package main

func main() {
    cards := newDeck()
    cards.print()
}

package main

import "fmt"

type card struct {
    value string
    suit  string
}

type deck []card

func newDeck() deck {
    cards := deck{}

    cardSuits := []string{"Spades", "Diamonds", "Hearts", "Clubs"}
    cardValues := []string{"Ace", "Two", "Three"}

    for _, suit := range cardSuits {
        for _, value := range cardValues {
            cards = append(cards, card{
                suit:  suit,
                value: value,
            })
        }
    }
    return cards
}

func (d deck) print() {
    for i, card := range d {
        fmt.Printf("%d) %s of %s\n", i, card.value, card.suit)
    }
}

❯ go version
go version go1.14.3 darwin/amd64

❯ go run main.go
# command-line-arguments
./main.go:4:11: undefined: newDeck