// Chapter 21 example: a validation loop where 0 is a good answer, and which
// stops when the input runs out.
// Run with: go run exercises/21/09-validate-volume.go

package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"
)

func main() {
	reader := bufio.NewReader(os.Stdin)

	var volume int
	for {
		fmt.Print("Volume (0 to 10): ")
		text, err := reader.ReadString('\n')
		line := strings.TrimSpace(text)
		if err != nil && line == "" {
			fmt.Println("No more input.")
			return
		}

		volume, err = strconv.Atoi(line)
		if err == nil && volume >= 0 && volume <= 10 {
			break
		}
		fmt.Println("That is not a volume from 0 to 10.")
	}

	fmt.Println("Volume set to", volume)
}