java - 为什么说我没弄错？

Question

在这个程序中，我应该返回我答对和错了多少题。但无论我记下什么，它都会说我答对了 20 个问题，错了 0 个。任何人都知道如何解决这个问题，这样它会比那个更准确？

类:

public class KNW_DriverExam
{
  //Create the arrays/Declare variable
  //Intialize theAnswers array
  private String[] theAnswers = {"B" , "D" , "A" , "A" , "C" ,
                              "A" , "B" , "A" , "C" , "D" , 
                              "B" , "C" , "D" , "A" , "D" , 
                              "C" , "C" , "B" , "D" , "A" };
  private String[] userAnswers;
  int[] missed = new int [theAnswers.length];

  /**The DriverExam method, recieves answers
    * @param Answer, the answer
    * */
  public KNW_DriverExam(String[] Answer)
  {
    userAnswers = new String[theAnswers.length];

    for(int i = 0; i < theAnswers.length; i++)
    {
      userAnswers[i] = theAnswers[i];
    }
  }

  /**The passed method, see if user passes or fails
    * @return true if user passed
    * @return false if user failed
    * */
  public boolean passed()
  {
    if(totalCorrect()>=15)
    {
      return true;
    }
    else
    {
      return false;
    }
  }

  /**The totalCorrect method, see how many user got right
    * @return correctCount, how many the user got right
    * */
  public int totalCorrect()
  {
    int correctCount = 0;

    for(int i = 0; i < theAnswers.length; i++)
    {
      if(userAnswers[i].equalsIgnoreCase(theAnswers[i]))
      {
        correctCount++;
      }
    }
    return correctCount;
  }

  /**The totalIncorrect method, how many the user got wrong
    * @return incorrectCount, how many the user got wrong
    * */
  public int totalIncorrect()
  {
    int incorrectCount = 0;

    for(int i = 0; i < theAnswers.length; i++)
    {
      if(!(userAnswers[i].equalsIgnoreCase(theAnswers[i])))
      {
        missed[incorrectCount] = i;
        incorrectCount++;
      }
    }
    return incorrectCount;
  }

  /**The missedQuestions method, how many quetions user missed.
    * @return missed, missed questions
    * */
  public int[] questionsMissed()
  {
    return missed;
  }
}

演示:

import java.util.Scanner;

public class KNW_DriverExamDemo
{
  public static void main(String[] args)
  {
    Scanner input = new Scanner(System.in);

    System.out.println("Driver's Exam/n");
    System.out.println("20 Multiple Choice Questions Mark A,B,C,D");

    //Inputting string
    String[] answers = new String[20];
    String answer;

    for(int i = 0; i < 20; i++)
    {
      do
      {
        System.out.println((i + 1) + ": ");
        answer = input.nextLine();
      }
      while(!isValidAnswer(answer));
      {

        answers[i] = answer;
      }
    }

    KNW_DriverExam exam = new KNW_DriverExam(answers);

    System.out.println("Results\n\n");

    System.out.println("Total Correct: " + exam.totalCorrect() + "\n");
    System.out.println("Total Incorrect: " + exam.totalIncorrect() + "\n");

    if(exam.totalIncorrect() > 0)
    {
      System.out.println("The Incorrect Answers Are: ");
      int missedIndex;

      for(int i = 0; i < exam.totalIncorrect(); i++)
      {
        missedIndex = exam.questionsMissed()[i] + 1;
        System.out.println(" " + missedIndex);
      }
    }
  }

  public static boolean isValidAnswer(String answer)
  {
    return "A".equalsIgnoreCase(answer) ||
      "B".equalsIgnoreCase(answer) ||
      "C".equalsIgnoreCase(answer) ||
      "D".equalsIgnoreCase(answer);
  }

Answer 1

看看你的构造函数。当您分配给 userAnswers 时，您使用的是 theAnswers 而不是提供的 Answer。

public KNW_DriverExam(String[] Answer) {
    userAnswers = new String[Answers.length];

    for(int i = 0; i < Answers.length; i++) {
        userAnswers[i] = Answers[i];
    }
}