Question

I’m trying to implement a time limit a user has to answer a question in a quiz. Although I have found quite a bit on timmers I don’t know how to piece it all together.

I want the user to have 15 seconds to answer the question. If they answer it in time, it checks if answer the answer is correct and then asks them if they want to continue to the next question.

If the user gives no response in the 15 seconds then it should say that the answer is incorrect and gives them the option to move to the next question.

Here is what I have so far.

for(int i=0; i<quiz.getQuizQuestions().size(); i++){

        super.getQuestion(i);

        //While timer is less than 15 seconds

        getResponse(i, questionStart);

        //If time has run out output "You have run out of time"

        super.nextQuestion();


}

It is probably worth knowing:

super.getQuestion(i) is just printing the question being asked

getResponse() is waiting for keyboard input. if something is entered then it checks to see if the user is correct.

super.nextQuestion() asks the user is they want to move onto the next question

Thanks in advance

EDIT: It would also be amazing if it was easy to implement a counter that counted down from 15 when converting this into a GUI.

Answer 1

uses ExecutorService and Future to make sure we read a line or interrupt it. Code is a little longer than I expected… Let me know if something is unclear:

import java.util.concurrent.*;
import java.io.*;    

public class Test {
    public static void main(String[] args) throws java.io.IOException {
        Question q = new Question();
        System.out.println("You have 5 seconds: " + q.toString());

        String userAnswer = null;    
        ExecutorService ex = Executors.newSingleThreadExecutor();
        try {
          Future<String> result = ex.submit(new GetInputLineCallable());
          try {
            userAnswer = result.get(5, TimeUnit.SECONDS);
            if (Integer.valueOf(userAnswer) == q.getAnswer()){
                System.out.println("good!");
            }
            else{
                System.out.println("Incorrect!");
            }

          } catch (ExecutionException e) {
            e.getCause().printStackTrace();
          } catch (TimeoutException e){
            System.out.println("too late!");
            return;
          } catch (InterruptedException e){
            System.out.println("interrupted?");
            e.getCause().printStackTrace();
          }

        } finally {
          ex.shutdownNow();
        }
    }
}



class GetInputLineCallable implements Callable<String> {
  public String call() throws IOException {
    BufferedReader inp = new BufferedReader(new InputStreamReader(System.in));
    String input = "";
    while ("".equals(input)) {
      try {
        while (!inp.ready()) {
          Thread.sleep(100);
        }
        input = inp.readLine();
      } catch (InterruptedException e) {
        return null;
      }
    } 
    return input;
  }
}




class Question{
  int p1, p2;
  public Question(){
    p1 = 2;
    p2 = 3;
  }
  public String toString(){
    return String.format("%d + %d = ?", p1, p2);
  }
  public int getAnswer(){
    return p1+p2;
  }  
}