fixed.go

func Play(quiz Quiz) {
	fmt.Println("You have", quiz.timer.secondsPerQuestion, "seconds per question.")
	input := make(chan string, len(quiz.questions))

	for _, question := range quiz.questions {
		timer := time.NewTimer(time.Duration(quiz.timer.secondsPerQuestion) * time.Second)

		fmt.Printf("Problem #%d: %s = ", question.id, question.question)
		go getInput(input)

		select {
		case <-timer.C:
			fmt.Println("Time limit exceed!")
		case answer := <-input:
			if answer == question.answer {
				quiz.score++
			}
		}
	}

	fmt.Printf("You scored %d out of %d.\n", quiz.score, len(quiz.questions))
}

func getInput(input chan string) {
	for {
		in := bufio.NewReader(os.Stdin)
		result, err := in.ReadString('\n')
		if err != nil {
			log.Fatal(err)
		}
		input <- strings.TrimSpace(result)
	}
}