我是新来的,正在做一个玩具问答游戏程序。我正在尝试实现一个计时器,当计时器结束时,测验结束。
这是我最初的实现。
func StartTimer(quizFinished chan bool, timer *time.Timer) {
// Start timer
<-timer.C
fmt.Println("\nQuiz has ended")
quizFinished <- true
return
}
func askQuestions(timer *time.Timer, questions []string, answers []string) []string {
var input string
var userAnswers []string
quizFinished := make(chan bool)
fmt.Println("Starting Quiz...")
go StartTimer(quizFinished, timer)
for index, element := range questions {
select {
case <-quizFinished:
fmt.Println("Quiz has ended")
return userAnswers
default:
fmt.Printf("Question %d: %s? ", index+1, element)
fmt.Scanln(&input)
userAnswers = append(userAnswers, input)
}
}
return userAnswers
}
编辑的实施
package main
import (
"bufio"
"flag"
"fmt"
"log"
"os"
s "strings"
"time"
)
func readFileData(fileName string) (questions []string, answers []string) {
file, err := os.Open(fileName)
if err != nil {
log.Fatalf("failed reading data from file: %v", err)
}
defer file.Close()
scanner := bufio.NewScanner(file)
for scanner.Scan() {
questionAndAnswer := s.Split(scanner.Text(), ",")
question, answer := questionAndAnswer[0], questionAndAnswer[1]
questions = append(questions, question)
answers = append(answers, answer)
}
return questions, answers
}
func askQuestions(timer *time.Timer, questions []string) []string {
var input string
var userAnswers []string = make([]string, 0, len(questions))
quizFinished := make(chan bool, 1)
fmt.Println("Starting Quiz...")
go func() {
<-timer.C
fmt.Println("\nquiz over...")
quizFinished <- true
}()
for index, element := range questions {
fmt.Printf("Question %d: %s? ", index+1, element)
answerCh := make(chan string, 1)
go func() {
fmt.Scanln(&input)
answerCh <- input
}()
select {
case <-quizFinished:
return userAnswers
case answer := <-answerCh:
userAnswers = append(userAnswers, answer)
}
}
return userAnswers
}
func main() {
fileNamePtr := flag.String("filename", "problems.csv", "Specify a file name to read in")
quizTimePtr := flag.Int("time", 5, "Specify how long the quiz should take")
flag.Parse()
timer := time.NewTimer(time.Duration(*quizTimePtr) * time.Second)
questions, answers := readFileData(*fileNamePtr)
// var userAnswers = askQuestions(timer, questions, answers)
var userAnswers = askQuestions(timer, questions)
correctAnswers := 0
incorrectAnswers := 0
for i := 0; i < len(answers); i++ {
if userAnswers[i] == answers[i] {
correctAnswers++
} else {
incorrectAnswers++
}
}
grade := float32(correctAnswers) / float32(len((questions)))
fmt.Printf("Total Questions: %d \n", len(questions))
fmt.Printf("Total Correct Answers: %d \n", correctAnswers)
fmt.Printf("Total Incorrect Answers: %d \n", incorrectAnswers)
fmt.Printf("Grade: %.0f%% \n", grade*100)
}
我一直得到以下输出和错误:
Starting Quiz...
Question 1: 5+5? 10
Question 2: 1+1?
Quiz has ended
2
Returning from quiz...
panic: runtime error: index out of range [2] with length 2
goroutine 1 [running]:
我对通道和goroutine的理解还不够好,无法理解发生了什么。预期的行为是,当计时器停止时,它打印“Quiz has ended”,并将一个值发送到quizFinished通道中,该值在select语句中读取。我遇到的另一个问题是Scanln将在测验结束后等待用户输入。感谢您的帮助!
1条答案
按热度按时间cvxl0en21#
当您在主goroutine中调用
Scanln
函数时,它会暂停并等待用户输入。即使你的计时器在另一个goroutine中结束并试图通知主goroutine,主goroutine也不会响应,因为它被“Scanner”阻止了。这就是为什么即使计时器结束,
Scanln
仍然在等待用户输入。