A simple program ask user to guess the number

guess-number.go

package main

import (
	"os"
	"fmt"
	"bufio"
	"strings"
	"strconv"
	"time"
	"math/rand"
)

func init() {
	rand.Seed(time.Now().UnixNano())
}

func askForInput(question string) (int, error) {
	AskAgain:
		fmt.Print(question)
		
		text, _ := bufio.NewReader(os.Stdin).ReadString('\n')
	
		if i, err := strconv.Atoi(strings.TrimSpace(text)); err != nil {
			printTips("Please enter number not string")
			goto AskAgain	
		}else{
			return i, nil
		}
}

func printTips(text string) {
	fmt.Printf("\n=> %s\n\n" ,text)
}

func main() {
	numberA, _ := askForInput("Please enter 1st number: ")	
	numberB, _ := askForInput("Please enter 2nd number: ")
	
	differenceNumber := numberB - numberA
	answerNumber     := numberA + (rand.Int() % (differenceNumber + 1))
	
	printTips(fmt.Sprintf("numberA=%d, numberB=%d, difference=%d, answer=%d", numberA, numberB, differenceNumber, answerNumber))
	
	for ;; {
		guessNumber, _ := askForInput("Please guess the answer: ")
		
		if guessNumber < numberA || guessNumber > numberB {
			printTips(fmt.Sprintf("The guess number out of range"))
			continue
		}
		
		if guessNumber == answerNumber {
			break
		}
		
		if (guessNumber >= answerNumber && guessNumber <= numberB) {
			numberB = guessNumber
		}
		
		if (guessNumber >= numberA && guessNumber <= answerNumber) {
			numberA = guessNumber
		}
		
		printTips(fmt.Sprintf("New range: %d to %d", numberA, numberB))
	}
	
	printTips(fmt.Sprintf("You win! The answer is %d", answerNumber))
}