CODEWITHSUNDEEP
go
amedeiros
amedeiros

Reputation: 949

GOLang Scanf error

When using Scanf twice the first time it gets the useres input but the second time it does not and returns out of the function. This is only a problem when running on Windows. When I run it on my Mac it works as expected first asking the uers for their username then their password. Below is the code in questions. I am not sure why it works fine on Mac but not on Windows. Any help in advance is appreciated. Thank you.

func credentials() (string, string) {

    var username string
    var password string

    fmt.Print("Enter Username: ")
    fmt.Scanf("%s", &username)

    fmt.Print("Enter Password: ")
    fmt.Scanf("%s", &password)

    return username, password
}

Upvotes: 6

Views: 4600

Answers (2)

Zombo
Zombo

Reputation: 1

You need to add newlines:

package main
import "fmt"

func main() {
   var user, pass string
   fmt.Scanf("%s\n", &user)
   fmt.Println(user)
   fmt.Scanf("%s\n", &pass)
   fmt.Println(pass)
}

alternatively, you can just use Scanln:

package main
import "fmt"

func main() {
   var user, pass string
   fmt.Scanln(&user)
   fmt.Println(user)
   fmt.Scanln(&pass)
   fmt.Println(pass)
}

https://golang.org/pkg/fmt#Scanln

Upvotes: 1

Chris
Chris

Reputation: 17535

Scanf is a bit finicky in that it uses spaces as a separator, and (at least for me) is rather unintuitive. Bufio does a good job of abstracting some of that:

func credentials() (string, string) {
    reader := bufio.NewReader(os.Stdin)

    fmt.Print("Enter Username: ")
    username, _ := reader.ReadString('\n')

    fmt.Print("Enter Password: ")
    password, _ := reader.ReadString('\n')

    return strings.TrimSpace(username), strings.TrimSpace(password) // ReadString() leaves a trailing newline character
}

Upvotes: 13

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