main.go

package main

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

func countdown(n uint) {
	for i := 0; i < int(n); i++ {
		fmt.Print(int(n) - i)
		<-time.After(1 * time.Second)
		fmt.Print(" ")
	}
	fmt.Println()
	fmt.Println("Start!!")
}

func input(ans chan int) {
	r := bufio.NewReader(os.Stdin)
	for {

		line, _, err := r.ReadLine()
		if err != nil {
			fmt.Print(">")
			continue
		}

		str := strings.Replace(string(line), "\r", "", -1)
		n, err := strconv.Atoi(str)
		if err != nil {
			fmt.Print(">")
			continue
		}
		ans <- n
	}
}

func main() {

	countdown(uint(5))

	ans := make(chan int)
	go input(ans)

	rnd := rand.New(rand.NewSource(time.Now().UnixNano()))
	count := 0
	for i := 1; i <= 10; i++ {
		n := rnd.Intn(100)
		m := rnd.Intn(100)
		fmt.Printf("%2d : %2d + %2d = ", i, n, m)
		select {
		case nm := <-ans:
			if nm == n+m {
				fmt.Println(">> correct!")
				count++
			} else {
				fmt.Println(">> wrong!!")
			}
		case <-time.After(5 * time.Second):
			fmt.Println()
			fmt.Println(">> timed out")
		}
	}

	fmt.Println("-----------------")
	fmt.Println("correct:", count)
}