How can I scan a rune?-CodePudding

So far, I haven't been able to print a rune by scanning it with fmt.Scan and printing it with fmt.Print. This is the vary basic code I'm working on:

package main

import "fmt"

func main() {
    var c rune
    fmt.Scan(&c)
    fmt.Printf("%c", c)
}

But it doesn't work, in fact, Printf doesn't produce any output. Instead, by manually assigning a char to my variable c (like var c rune = 'a', without using fmt.Scan), I'm able to print the wanted rune. How can I scan a rune?

CodePudding user response：

here are two methods:

package fmt

import (
   "fmt"
   "strings"
)

func scan_fmt(s string) (rune, error) {
   var c rune
   _, err := fmt.Sscanf(s, "%c", &c)
   if err != nil {
      return 0, err
   }
   return c, nil
}

func scan(s string) (rune, error) {
   c, _, err := strings.NewReader(s).ReadRune()
   if err != nil {
      return 0, err
   }
   return c, nil
}

https://godocs.io/strings#Reader.ReadRune

CodePudding user response：

As we know Scan return n and err so please check for error under Scan statement as follows

n, err := fmt.Scan(&c)
    if err != nil {
        fmt.Println(err)
    }

It will clearly show you the error and why it was ignored.

Other than the above, please try it locally on your own laptop instead of the playground because on the playground it most of the time gives an EOF error as most of them do not support reading from the terminal.

I hope the above helps you in debugging the issue.

Other Reference:

Scanf ignores if not provided \n