Add a method addText to the Question class of How To 10.1 and provide a different implementation of ChoiceQuestion that calls addText rather than storing an array list of choices.

Complete the following files:

/** A question with multiple choices. */ public class ChoiceQuestion extends Question { // Add any needed instance variables, but don't store the choices // The choices should be added to the text of the superclass /** Constructs a choice question with a given text and no choices. @param questionText the text of this question */ public ChoiceQuestion(String questionText) { ... } /** Adds an answer choice to this question. @param choice the choice to add @param correct true if this is the correct choice, false otherwise */ public void addChoice(String choice, boolean correct) { ... } }

/** A question with a text and an answer. */ public class Question { private String text; private String answer; /** Constructs a question with a given text and an empty answer. @param questionText the text of this question */ public Question(String questionText) { text = questionText; answer = ""; } /** Sets the answer for this question. @param correctResponse the answer */ public void setAnswer(String correctResponse) { answer = correctResponse; } /** Checks a given response for correctness. @param response the response to check @return true if the response was correct, false otherwise */ public boolean checkAnswer(String response) { return response.equals(answer); } /** Add a line of text to the question text. */ public void addLine(String line) { ... } /** Displays this question. */ public void display() { System.out.println(text); } }

Use the following file:

import java.util.Scanner;

public class QuestionDemo
   public static void main(String[] args)
      Question[] quiz = new Question[2];

      quiz[0] = new Question("Who was the inventor of Java?");
      quiz[0].setAnswer("James Gosling");      

      ChoiceQuestion question = new ChoiceQuestion(
         "In which country was the inventor of Java born?");
      question.addChoice("Australia", false);
      question.addChoice("Canada", true);
      question.addChoice("Denmark", false);
      question.addChoice("United States", false);
      quiz[1] = question;

      Scanner in = new Scanner(;
      for (Question q : quiz)
         System.out.println("Your answer: ");
         String response = in.nextLine();