Golang : Scanf function weird error in Windows



Tags : golang scanf bufio readstring

Got a newbie to Golang asking for help in the Golang Facebook group and he is having trouble getting his simple codes to work. Apparently this code :

 package main

 import "fmt"

 func main() {
 var x [5]string
 fmt.Println("Enter your friends name in the list")
 for i := 0; i < len(x); i++ {
 fmt.Println(i)
 fmt.Scanf("%s", &x[i])
 fmt.Println(x[i])
 }
 }

was working fine in *nix based OS. Scanf function was able to capture the user input without trouble. But not the case with Windows ( the Golang version is go1.3.3 windows/386).

It seems that under Windows, Scanf accepted the input twice and thus causing the for loop to end earlier than it suppose too. See picture

screen shot of scanf error

To bypass this Scanf "bug" until it was fixed in future version of Golang. Replace Scanf with bufio's ReadString function to capture user input from ... standard input (os.Stdin)

 package main

 import (
 "bufio"
 "fmt"
 "os"
 )

 func main() {

 var x [5]string

 reader := bufio.NewReader(os.Stdin)

 fmt.Println("Enter your friends name in the list")

 for i := 0; i < len(x); i++ {
 fmt.Println(i)
 x[i], _ = reader.ReadString('\n')

 fmt.Println(x[i])
 }
 }

This replacement codes have been tested on Windows and Linux/MacOSX and confirmed to be working. Hope this tutorial can be useful to you.

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Tags : golang scanf bufio readstring

By Adam Ng

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