java - 从文件加载到数组列表时出现问题

Question

所以我正在编写一个测验程序，其中包含不确定的问题数量(用 Java)，并且我在完成以下事情时遇到问题:

1) 从文件加载测验问题并存储在数组列表中并访问它(需要帮助!)2)正确答案不被接受 - 给我错误(逻辑错误)3) 并未显示所有答案选项

代码如下:

import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;

public class Quiz {

 public void writeFile() {
   Question qn = new Question();
   try {
     PrintWriter out = new PrintWriter("quiz.txt");
     out.println(qn.Question);
     out.println(qn.numberOfChoices);
     qn.answerChoices = new String[qn.numberOfChoices];
     for (int i = 0; i < qn.numberOfChoices; i++) {
         out.println(qn.answerChoices[i]);
     }
     out.println(qn.correctAnswer);
     out.println(qn.numOfTries);
     out.println(qn.numOfCorrectTries);
     out.close();
   } catch (IOException f) {
     System.out.println("Error.");
   }
   qn.getQuestion();
 }

 public void readFile() {
     File file = new File ("quiz.txt");
     boolean exists = file.exists();
     Quiz q = new Quiz();
     Question a = new Question();
     List<String> question = new ArrayList<String>();
     String[] answerChoices = a.answerChoices;
     try {
        if (exists == true) {
            Scanner s = new Scanner(file);
            a.Question = s.nextLine();
            a.numberOfChoices = s.nextInt();
            a.answerChoices = new String[a.numberOfChoices];
            for (int i = 0; i < a.numberOfChoices; i++) {
                a.answerChoices[i] = s.nextLine();
            }
            s.nextLine();
            a.correctAnswer = s.nextInt();
            a.numOfTries = s.nextInt();
            a.numOfCorrectTries = s.nextInt();
            a.getQuestion();
         } else {
            q.writeFile();
         }
     } catch (IOException e) {
       System.out.println("File not found.");
     }
 }

public static void main (String[] args) {
    Scanner in = new Scanner(System.in);
    Quiz qz = new Quiz();
    Question b = new Question();
    int Selection;
    List<String> question = new ArrayList<String>();

    System.out.println("Welcome to the Quiz Program! Good luck!");
    do {
       qz.readFile();
       System.out.println("Your answer?: ");
       Selection = in.nextInt();
       if (Selection == b.correctAnswer) {
          b.numOfCorrectTries++;
          b.getQuestion();
       } else {
          b.getQuestion();
       }
    } while (Selection < b.numberOfChoices);
    while (Selection > b.numberOfChoices || Selection < 0) {
       System.out.println("Error. Try again");
       System.out.println("Your answer?: ");
       Selection = in.nextInt();
    }
  }
}

和问题类别:

import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;

public class Question {

 int correctAnswer;
 int numOfTries;
 int numOfCorrectTries;
 int numberOfChoices;
 String Question;
 String[] answerChoices;

 public Question() {

 }
 public void getQuestion() {
    System.out.println("Question: " + Question);
    System.out.println("Answer: ");
    for (int i = 0; i < numberOfChoices; i++) {
        System.out.println(answerChoices[i]);
    }
 }

 public double getPercentageRight() {
     double percentageRight = (numOfCorrectTries / numOfTries) * 100;
     percentageRight = Math.round(percentageRight * 100);
     percentageRight = percentageRight / 100;
     return percentageRight;
 }
}  

测验.TXT:

How many licks does it take to get to the tootsie roll center of a  
tootsie pop?
4
one
two
three
four
2
14
5
What is your name?
3
Arthur, King of the Britons
Sir Lancelot the Brave
Sir Robin the Not-Quite-So-Brave-As-Sir Lancelot
0
14
6
Who's on first?
5
What
Why
Because
Who
I don't know
3
14
7
Which of the following is a terror of the fire swamp?
4
Lightning sand
Flame spurt
R.O.U.S.
All of the above
3
14
4
Who is the all-time greatest pilot?
6
Manfred von Richthofen
Chuck Yeager
Hiraku Sulu
Luke Skywalker
Kara Thrace
Charles Lindbergh
4
14
9

Answer 1

一些问题:

您的List<String> question = new ArrayList<String>();应该是类似 List<Question> questionBank = new ArrayList<Question>();因为将所有内容都保存为字符串(而不是 Question 对象)会更加困惑。名称questionBank也比 question 更具描述性阅读代码时。我还建议使用 questionBank作为类变量，因此可以在您的 Quiz 中轻松访问它类(class)。

您从未将问题添加到 ArrayList 中，但我怀疑您已经知道这一点，并且在解决其他问题时它的优先级较低。

您的Question类(class)也有点不合常规。更好的结构方式可能是这样的:

public class Question {

     private int correctAnswer;
     private int numOfTries;
     private int numOfCorrectTries;
     private String question;
     private String[] answerChoices;

     public Question(String question, String[] answerChoices,
             int correctAnswer, int numOfTries, int numOfCorrectTries) {
         this.question = question;
         this.answerChoices = answerChoices;
         this.correctAnswer = correctAnswer;
         this.numOfTries = numOfTries;
         this.numOfCorrectTries = numOfCorrectTries;
     }

     public void getQuestion() {
            System.out.println("Question: " + question);
            System.out.println("Answer: ");
            for (int i = 0; i < answerChoices.length; i++) {
                System.out.println(answerChoices[i]);
            }
     }

     public double getPercentageRight() {
         double percentageRight = (numOfCorrectTries / numOfTries) * 100;
         percentageRight = Math.round(percentageRight * 100);
         percentageRight = percentageRight / 100;
         return percentageRight;
     }

}

我删除了 numberOfChoices 的变量因为这与 answerChoices.length 相同。我还重命名了你的Question至question因为Java中的变量通常遵循驼峰命名法。我不确定其他方法的用途或它们应如何显示输出，所以我大多不理会它们。

为了读取文件，我认为您可以执行与您所拥有的类似的操作，但我将发布符合 Question 的新构造函数的代码。类。

private void addQuestions() {
    File quizText = new File("quiz.txt");
    try {
        Scanner fileIn = new Scanner(quizText);
        while (fileIn.hasNextLine()) {
            String question = fileIn.nextLine();
            int numberOfAnswers = fileIn.nextInt();
            fileIn.nextLine();
            String[] answers = new String[numberOfAnswers];
            for (int i = 0; i < numberOfAnswers; i++) {
                answers[i] = fileIn.nextLine();
            }
            int correctAnswer = fileIn.nextInt();
            int numOfTries = fileIn.nextInt();
            int numOfCorrectTries = fileIn.nextInt();
            fileIn.nextLine();
            Question nextQuestion =
                new Question(question, answers, correctAnswer, numOfTries, numOfCorrectTries);
            questionBank.add(nextQuestion);
        }
        fileIn.close();
    } catch (IOException e){
        e.printStackTrace();
        System.out.println("File Not Found.");
        return;
    }
}

我还将变量设为私有(private)，但您可以为它们创建自定义 getter，以防止从外部直接访问(和/或更改)它们。使用此代码，我能够创建一个包含所有五个问题的问题库，并显示正确的答案以及所有可能的选择，因此希望它能为您指明正确的方向。