A question about constructor

I got this piece of code from a book:
public class Bala{
int x, y;
Bala(int x1, int y1){
x=x1;
y=y1;
Bala(final Bala bala){ //here
x=bala.x;
y=bala.y;
What is the purpose of "final" here. I wrote a simple test programm to do the constructor with and without "final" and couldn't see any differences. Any help would be appreciated.

There is no need for final in your case, but look at this example:
public void init(final Bala bala) {
Button b = new Button();
b.addActionListener(new ActionListener() { // anonymous inner class
    public void actionPerformed(ActionEvent e) {
      // This part of the code is run when you press the button.
      // you can use bala here in this inner class,
      // but only because you made bala final.
     // (Doesn't matter if you do it from a method or constructor)
      bala.x = 5;
}I don't know other reasons where you would make it final. Making bala final, means that you can't modify it inside the init() method, i.e. you can't refer to another bala object, and you can't set it to null.

Similar Messages

Some question about constructor

The code below shows some of the text for a class called City. As you can see, a City has two instance variables, name and population. Write a complete public constructor (including header line) with no parameters, which sets the population to an initial value of -1, and the name to an initial value of "unknown".
this is the question:
this is what I wrote:
public class City {
private String name;
private int population;
public City(String n, int p){
name = n;
population = p;
public City(){
name = "unknown";
population = -1;
} y is it wrong?

Umass wrote:
The code below shows some of the text for a class called City. As you can see, a City has two instance variables, name and population. Write a complete public constructor (including header line) with no parameters, which sets the population to an initial value of -1, and the name to an initial value of "unknown".
this is the question:
this is what I wrote:
public class City {
private String name;
private int population;
public City(String n, int p){
name = n;
population = p;
public City(){
name = "unknown";
population = -1;
} y is it wrong?The comment about the missing closing brace appears to be correct. It would help if you'd post the compiler message instead of just telling us that it's "wrong". More info, please.
The code you posted isn't wrong, once you make that correction, but it's not the way I'd write it.
Here's what I would do:
public class City
 private static final String DEFAULT_NAME = "unknown";
 private static final int DEFAULT_POPULATION = 0;
 private String name;
 private int population;
 public City()
 this(DEFAULT_NAME, DEFAULT_POPULATION);
 public City(String name, int population)
 setName(name);
 setPopulation(population);
 private void setName(String name)
 if (name == null)
 throw new IllegalArgumentException("name cannot be null");
 this.name = name;
 private void setPopulation(int population)
 if (population < 0)
 throw new IllegalArgumentException("population cannot be negative");
 this.population = population;
}Here's why:
(1) No magic constants. I like having static final constants with a name that spells out what it's for. Better than comments, no ambiguity for users. A negative population makes no sense to me, but zero does.
(2) Objects should be fully initialized and ready to go. Write one constructor that fully initializes the object, every attribute. I like to do it with setters, because I can embed any rules for sensible values there. They protect both the constructor and any public setters that I might have without duplicating code. I made the setters private because I didn't want my City to be mutable.
(3) Have your default constructor call the full constructor. It makes clear what the default values are (in javadocs, preferrably).
%

Question about constructors and inheritance

Hello:
I have these classes:
public class TIntP4
 protected int val=0;
 public TIntP4(){val=0;}
 public TIntP4(int var)throws Exception
 if(var<0){throw new Exception("TIntP4: value must be positive: "+var);}
 val=var;
 public TIntP4(String var)throws Exception
 this(Integer.parseInt(var));
 public String toString()
 return val+"";
public class TVF extends TIntP4
}Using those clases, if I try to compile this:
TVF inst=new TVF("12");I get a compiler error: TVF(String) constructor can not be found. I wonder why constructor is not inherited, or if there is a way to avoid this problem without having to add the constructor to the subclass:
public class TVF extends TIntP4
 public TVF (String var)throws Exception
 super(var);
}Thanks!!

I guess that it would not help adding the default constructor:
public class TVF extends TIntP4
 public TVF ()
 super();
 public TVF (String var)throws Exception
 super(var);
}The point is that if I had in my super class 4 constructors, should I implement them all in the subclass although I just call the super class constructors?
Thanks again!

Questions about a MasterQuize program

Hi, everyone.
I got a in-class case study program like this in the class:
* This class stores/represents a question that has one of two
* answers: True or False.
* 
* It needs to track the following information:
* <ul>
* <li>Question text</li>
* <li>Correct answer</li>
* <li>The user's answer to the question</li>
* <li>Points value</li>
* <li>Category</li>
* <li>Difficulty rating</li>
* </ul>
// Our question should allow us to do the following:
// - Create question (constructor) -- may be overloaded
// - Print (display) question
// - Check client's answer for correctness
// - Get points value for question (0 or max)
// - Add "No-BS" grading option
// - Getting client's answer
// - Check to see if answered by client
public class TrueFalseQuestion
 // Class constants (to simplify changes to common values)
 public static final int MIN_DIFFICULTY_LEVEL = 1;
 public static final int MAX_DIFFICULTY_LEVEL = 5;
 public static final int DEFAULT_DIFFICULTY_LEVEL = 1;
 public static final int DEFAULT_POINT_VALUE = 1;
 public static final String DEFAULT_CATEGORY_VALUE = "none";
 // Class instance variables
 private String questionText;
 private String correctAnswer;
 private String userAnswer;
 private int pointsValue;
 private String category;
 private int difficultyLevel; // TODO: Set a range for difficulty levels
 * @param text The literal wording of this question
 * @param answer The correct answer for this question
 * @param pts The total points available for this question
 * @param ctgry Category keyword for this question
 * @param level The perceived/intended difficulty level of this question
 * 
 * Defines a TrueFalseQuestion object.
 public TrueFalseQuestion (String text, String answer, int pts, String ctgry, int level)
 // Set starting values for all instance variables
 questionText = text.trim();
 correctAnswer = answer.trim();
 userAnswer = null; // No user answer supplied yet
 if (pts >= 1) // We assume that every problem is worth at least 1 point
 pointsValue = pts;
 else
 pointsValue = DEFAULT_POINT_VALUE;
 category = ctgry.trim();
 if (level >= MIN_DIFFICULTY_LEVEL && level <= MAX_DIFFICULTY_LEVEL) // within range
 difficultyLevel = level;
 else
 difficultyLevel = DEFAULT_DIFFICULTY_LEVEL;
 // Simplified (overloaded) constructors
 * @param text The literal wording of this question
 * @param answer The correct answer for this question
 * @param pts The total points available for this question
 * 
 * Defines a TrueFalseQuestion with default values for category and difficulty level.
 public TrueFalseQuestion (String text, String answer, int pts)
 // Call pre-existing constructor with default category and difficulty
 this(text, answer, pts, DEFAULT_CATEGORY_VALUE, DEFAULT_DIFFICULTY_LEVEL);
 * @param text The literal wording of this question
 * @param answer The correct answer for this question
 * 
 * Defines a TrueFalseQuestion with the default point value, default category,
 * and default difficulty level.
 public TrueFalseQuestion (String text, String answer)
 // Call pre-existing constructor with default points, category and difficulty
 this(text, answer, DEFAULT_POINT_VALUE, DEFAULT_CATEGORY_VALUE,
 DEFAULT_DIFFICULTY_LEVEL);
 * @param text The literal wording of this question
 * @param answer The correct answer for this question
 * @param pts The total points available for this question
 * @param ctgry Category keyword for this question
 * 
 * Defines a TrueFalseQuestion with the default difficulty level.
 public TrueFalseQuestion (String text, String answer, int pts, String ctgry)
 // Call pre-existing constructor with default points, category and difficulty
 this(text, answer, pts, ctgry,
 DEFAULT_DIFFICULTY_LEVEL);
 * @param text The literal wording of this question
 * @param answer The correct answer for this question
 * @param ctgry Category keyword for this question
 * 
 * Defines a TrueFalseQuestion with the default point value and the default
 * difficulty level.
 public TrueFalseQuestion (String text, String answer, String ctgry)
 // Use default points and difficulty
 this(text, answer, DEFAULT_POINT_VALUE, ctgry, DEFAULT_DIFFICULTY_LEVEL);
 * @param text The literal wording of this question
 * @param answer The correct answer for this question
 * @param pts The total points available for this question
 * @param level The perceived/intended difficulty level of this question
 * 
 * Defines a TrueFalseQuestion with the default value for the question category.
 public TrueFalseQuestion (String text, String answer, int pts, int level)
 // Use default category
 this(text, answer, pts, DEFAULT_CATEGORY_VALUE, level);
 // Clients can invoke this method to retrieve the text of the current question.
 // We chose to return the text instead of printing it; this allows the client
 // to decide how it should be presented (via a GUI, over a network, etc.)
 public String getQuestion ()
 return questionText;
 // This method allows the client to store the user's answer inside the
 // TrueFalseQuestion object for easy comparison
 public void submitAnswer (String ans)
 userAnswer = ans;
 // This method reports whether the submitted answer matches the correct answer
 public boolean answerIsCorrect(String userAns) // This version does all the work
 if (userAns == null) // No response from user (yet)
 return false;
 else
 // Normalize and compare answers
 char key = normalize(correctAnswer); // Get 't' or 'f'
 char ans = normalize(userAns); // Get 't' or 'f'
 return (key == ans);
 public boolean answerIsCorrect ()
 return answerIsCorrect(userAnswer); // Call previously-defined version
 public int getPointsValue()
 return pointsValue;
 // Return the points awarded for the user's answer. This method does
 // NOT support partial credit; answers are either correct or incorrect.
 // If the "No-BS" option is selected, blank (unanswered) questions receive
 // 1 point automatically; otherwise, the score will be either 0 or the
 // question's normal points value.
 public int getPointsEarned(boolean useNoBSRule)
System.out.println("useNoBS: " + useNoBSRule + "\tuserAnswer: " + userAnswer + "\tcorrectAnswer: " + correctAnswer);
 if (useNoBSRule && (userAnswer == null))
 return 1;
 else if (userAnswer == null)
 return 0; // Without "No-BS", treat blank problems as incorrect
 if (answerIsCorrect() == false)
 return 0;
 else
 return pointsValue;
 // This method returns true if the user has submitted an answer
 // for this question (regardless of whether that answer is correct)
 public boolean hasBeenAnswered ()
 return (userAnswer != null);
 // Private helper method to convert all answers to single lowercase
 // letters (in this case, 't' for TRUE and 'f' for FALSE)
 private char normalize (String input)
 if (input != null)
 input = input.trim(); // Remove leading whitespace
 input = input.toLowerCase();
 return input.charAt(0);
 else
 return ' ';
import java.util.*;
* This class represents a complete test or quiz.
* Data stored:
* - List of questions
* - Total score earned
* - Total score possible
* - Name/title of test
* - Instructions
* - Category/class assignment
* - Student (test-taker) name
* - Date test is/was taken
* - Time started
* - Time completed
* - Maximum time allotted
* - (List of) Maximum attempts per question
* - List of attempts per question
* - List of difficulty ratings per question
* - Assignment weight
* Methods:
* - Constructor
* - Add question
* - Display question
* - Display test
* - Display instructions
* - Generate random exam
* - Take/administer test
* - Get score
* STUFF TO DO:
* - Add time/date restrictions
* - Add network access restrictions
* - Add other restrictions/allowances?
* @author (your name)
* @version (a version number or a date)
public class Test
 // Class constant
 public static final int MAX_NUMBER_OF_QUESTIONS = 10;
 // Class instance variables
 private String testName;
 private int scoreEarned; // What the student earned on the exam
 private int scorePossible; // Total point values of all questions
 private String instructions; // Exam header text
 private ArrayList<TrueFalseQuestion> questions; // Create inside constructor
 // Methods
 public Test (String name, String instr)
 testName = name;
 scoreEarned = 0;
 scorePossible = 0;
 instructions = instr;
 questions = new ArrayList<TrueFalseQuestion>(); //[MAX_NUMBER_OF_QUESTIONS];
 public String getInstructions()
 return instructions;
 public int getScore()
 return scoreEarned;
 public void addQuestion (TrueFalseQuestion q)
 scorePossible += q.getPointsValue();
 questions.add(q); // Automatically append question to end of test
 public String displayQuestion (int position)
 if (position < questions.size())
 return (position+1) + ". " + questions.get(position).getQuestion();
 else
 return null;
 public String displayTest ()
 String result = "";
 for (int i = 0; i < questions.size(); i++)
 result += (i+1) + ". (";
 TrueFalseQuestion t = questions.get(i);
 result += t.getPointsValue();
 result += " points)\n\n" + displayQuestion(i);
 result += "\n\n";
 return result;
 // Get test length (number of questions)
 public int length ()
 return questions.size();
 // Submit answer to a specific question
 public boolean answer(int number, String a)
 // Question numbers run from 0-(max-1) -- THIS WAS AN OFF-BY-ONE ERROR AT FIRST
 if (number >= 0 && number < questions.size())
 TrueFalseQuestion t = questions.get(number);
 t.submitAnswer(a);
 return true; // Question was answered
 else
 return false; // Unable to answer (nonexistent) question
 // Score exam
 public void scoreExam (boolean useNoBS)
 scoreEarned = 0;
 for (int i = 0; i < questions.size(); i++) // For each question in exam
 TrueFalseQuestion t = questions.get(i); // get current question
 scoreEarned += t.getPointsEarned(useNoBS);
}// Test harness for the Test and *Question classes
import java.util.*;
public class QuizDriver
 public static void main(String[] args)
 // Create a new Test object
 Test exam = new Test("Sample Exam", "Select the correct answer for each question");
 setUp(exam);
 Scanner sc = new Scanner(System.in);
 System.out.println(exam.getInstructions());
 // Administer exam
 for (int i = 0; i < exam.length(); i++)
 // Print out current question
 System.out.println(exam.displayQuestion(i));
 // Get user answer
 System.out.print("Your answer: ");
 String ans = sc.nextLine();
 if (ans.equals("")) // Handle blank responses for unanswered questions
 ans = null;
 exam.answer(i, ans);
 // Get exam results
 exam.scoreExam(true);
 System.out.println("Your final score was " + exam.getScore() + " points.");
 private static void setUp (Test t)
 TrueFalseQuestion x = new TrueFalseQuestion("The sky is blue.", "true", 2);
 t.addQuestion(x);
 x = new TrueFalseQuestion("The first FORTRAN compiler debuted in 1957", "true", 5);
 t.addQuestion(x);
 x = new TrueFalseQuestion("Spock was a Vulcan", "false", 3);
 t.addQuestion(x);
}This program is far from finishing.
I have many questions about this program, but let me ask this one first:
In the TrueFalseQeustion class, why are there so many constructors? What is the purpose of setting some of the variables to default values?
Thank you very much!!!
Edited by: Terry001 on Apr 16, 2008 10:02 AM

newark wrote:
Stop ignoring the error messages. You seem to think that an error message means you're doing the assignment wrong. It's probably a simple fix. Post the exact error messages, as well as the code that corresponds to them. The error message will tell you exactly what line the problem occurs on, so you know right where to look.Hi,
After some modifications, the program now gives me the result the assignment wants when I run it. But I still have trouble with the MultipleChoiceQuestion class
Here is the complete program
QuizDriver class
// Test harness for the Test and *Question classes
import java.util.*;
public class QuizDriver
 public static void main(String[] args)
 // Create a new Test object
 Test exam = new Test("Sample Exam", "Select the correct answer for each question");
 setUp(exam);
 Scanner sc = new Scanner(System.in);
 System.out.println(exam.getInstructions());
 // Administer exam
 for (int i = 0; i < exam.length(); i++)
 // Print out current question
 System.out.println(exam.displayQuestion(i));
 // Get user answer
 System.out.print("Your answer: ");
 String ans = sc.nextLine();
 if (ans.equals("")) // Handle blank responses for unanswered questions
 ans = null;
 exam.answer(i, ans);
 // Get exam results
 exam.scoreExam(true);
 System.out.println("Your final score was " + exam.getScore() + " points.");
 private static void setUp (Test t)
 Question x;
 x = new TrueFalseQuestion("The sky is blue.", "true", 2);
 t.addQuestion(x);
 x = new TrueFalseQuestion("The first FORTRAN compiler debuted in 1957", "true", 5);
 t.addQuestion(x);
 x = new TrueFalseQuestion("Spock was a Vulcan", "false", 3);
 t.addQuestion(x);
 x = new MultipleChoiceQuestion("What is the color of the car\na.Red\nb.Green", "a. Red", 3);
 t.addQuestion(x);
 x = new MultipleChoiceQuestion("What is the name of this class\na.CSE110\nb.CSE114", "b, CSE114", 3);
 t.addQuestion(x);
}Test
public class Test
 // Class constant
 public static final int MAX_NUMBER_OF_QUESTIONS = 10;
 // Class instance variables
 private String testName;
 private int scoreEarned; // What the student earned on the exam
 private int scorePossible; // Total point values of all questions
 private String instructions; // Exam header text
 private ArrayList<Question> questions; // Create inside constructor
 // Methods
 public Test (String name, String instr)
 testName = name;
 scoreEarned = 0;
 scorePossible = 0;
 instructions = instr;
 questions = new ArrayList<Question>(); //[MAX_NUMBER_OF_QUESTIONS];
 public String getInstructions()
 return instructions;
 public int getScore()
 return scoreEarned;
 public void addQuestion (Question q)
 scorePossible += q.getPointsValue();
 questions.add(q); // Automatically append question to end of test
 public String displayQuestion (int position)
 if (position < questions.size())
 return (position+1) + ". " + questions.get(position).getQuestion();
 else
 return null;
 public String displayTest ()
 String result = "";
 for (int i = 0; i < questions.size(); i++)
 result += (i+1) + ". (";
 Question t = questions.get(i);
 result += t.getPointsValue();
 result += " points)\n\n" + displayQuestion(i);
 result += "\n\n";
 return result;
 // Get test length (number of questions)
 public int length ()
 return questions.size();
 // Submit answer to a specific question
 public boolean answer(int number, String a)
 // Question numbers run from 0-(max-1) -- THIS WAS AN OFF-BY-ONE ERROR AT FIRST
 if (number >= 0 && number < questions.size())
 Question t = questions.get(number);
 t.submitAnswer(a);
 return true; // Question was answered
 else
 return false; // Unable to answer (nonexistent) question
 // Score exam
 public void scoreExam (boolean useNoBS)
 scoreEarned = 0;
 for (int i = 0; i < questions.size(); i++) // For each question in exam
 Question t = questions.get(i); // get current question
 scoreEarned += t.getPointsEarned(useNoBS);
}Question
public class Question
// Class constants
public static final int MIN_DIFFICULTY_LEVEL = 1;
public static final int MAX_DIFFICULTY_LEVEL = 5;
public static final int DEFAULT_DIFFICULTY_LEVEL = 1;
public static final int DEFAULT_POINT_VALUE = 1;
public static final String DEFAULT_CATEGORY_VALUE = "none";
// Class instance variables
protected String questionText;
protected String correctAnswer;
protected String userAnswer;
protected int pointsValue;
protected String category;
protected int difficultyLevel; //TODO: set a range for difficulty levels
// Constructors
public Question (String text, String answer, int pts, String ctgry, int level)
 questionText = text.trim();
 correctAnswer = answer.trim();
 userAnswer = null;
 if (pts >= 1)
 pointsValue = pts;
 else
 pointsValue = DEFAULT_POINT_VALUE;
 category = ctgry.trim();
 if (level >= MIN_DIFFICULTY_LEVEL && level <= MAX_DIFFICULTY_LEVEL)
 difficultyLevel = level;
 else
 difficultyLevel = DEFAULT_DIFFICULTY_LEVEL;
 // Overloaded (simplied) constructors
 public Question (String text, String answer, int pts)
 this(text, answer, pts, DEFAULT_CATEGORY_VALUE, DEFAULT_DIFFICULTY_LEVEL);
 public Question (String text, String answer, int pts, String ctgry)
 this(text, answer, pts, ctgry, DEFAULT_DIFFICULTY_LEVEL);
 public Question (String text, String answer, String ctgry)
 this(text, answer, DEFAULT_POINT_VALUE, ctgry, DEFAULT_DIFFICULTY_LEVEL);
 public Question (String text, String answer, int pts, int level)
 this(text, answer, pts, DEFAULT_CATEGORY_VALUE, level);
 // Methods
 public String getQuestion ()
 return questionText;
 // Use this method to store user answers
 public void submitAnswer (String ans)
 userAnswer = ans;
 public boolean answerIsCorrect (String userAns)
 if (userAns == null)
 return false;
 else
 // Normalize and compare answers
 char key = normalize (correctAnswer); //Get the first letter of an answer
 char ans = normalize (userAns); //Get the first letter of an answer
 return (key == ans);
 public boolean answerIsCorrect ()// Why do we need two answerisCorrect() methods?
 return answerIsCorrect (userAnswer);
 public int getPointsValue ()
 return pointsValue;
 public int getPointsEarned (boolean userNoBSRule)
 System.out.println ("useNoBS: " + userNoBSRule + "\tuseAnswer: " + userAnswer + "\tcorrectAnswer: " + correctAnswer);
 if (userNoBSRule && (userAnswer == null))
 return 1;
 else if (userAnswer == null)
 return 0;
 if (answerIsCorrect() == false)
 return 0;
 else
 return pointsValue;
 public String getCorrectAnswer ()
 return correctAnswer;
 public boolean hasBeenAnswered ()
 return (userAnswer != null);
 private char normalize (String input)
 if (input != null)
 input = input.trim();
 input = input.toLowerCase();
 return input.charAt(0);
 else
 return ' ';
 TrueFalseQuestion
public class TrueFalseQuestion extends Question
public TrueFalseQuestion (String text, String answer, int pts, String ctgry, int level)
 super(text, answer, pts, ctgry, level);
 public TrueFalseQuestion (String text, String answer, int pts)
 super(text, answer, pts, DEFAULT_CATEGORY_VALUE, DEFAULT_DIFFICULTY_LEVEL);
 public TrueFalseQuestion (String text, String answer, int pts, String ctgry)
 super(text, answer, pts, ctgry, DEFAULT_DIFFICULTY_LEVEL);
 public TrueFalseQuestion (String text, String answer, String ctgry)
 super(text, answer, DEFAULT_POINT_VALUE, ctgry, DEFAULT_DIFFICULTY_LEVEL);
 public TrueFalseQuestion (String text, String answer, int pts, int level)
 super(text, answer, pts, DEFAULT_CATEGORY_VALUE, level);
 // Methods
 public String[] getPossibleAnswerChoice ()
 String[] possibleAnswerChoice = {"true", "false"};
 return possibleAnswerChoice;
} MultipleChoiceQuestion
public class MultipleChoiceQuestion extends Question
 public MultipleChoiceQuestion (String text, String answer, int pts, String ctgry, int level)
 super(text, answer, pts, ctgry, level);
 public MultipleChoiceQuestion (String text, String answer, int pts)
 super(text, answer, pts, DEFAULT_CATEGORY_VALUE, DEFAULT_DIFFICULTY_LEVEL);
 public MultipleChoiceQuestion (String text, String answer, int pts, String ctgry)
 super(text, answer, pts, ctgry, DEFAULT_DIFFICULTY_LEVEL);
 public MultipleChoiceQuestion (String text, String answer, String ctgry)
 super(text, answer, DEFAULT_POINT_VALUE, ctgry, DEFAULT_DIFFICULTY_LEVEL);
 public MultipleChoiceQuestion (String text, String answer, int pts, int level)
 super(text, answer, pts, DEFAULT_CATEGORY_VALUE, level);
 // Methods
 String possibleAnswers;
 public String getPossibleAnswers ()
 return possibleAnswers;
 public void addAnswerChoice (String answerChoice)
 String ansChoice = answerChoice;
 questionText += "\nansChoice";
 possibleAnswers = answerChoice;
 public void printAnswerChoice ()
 System.out.println (questionText);
} I don't understand why the assignment wants me to build a method in the MultpleChoiceQuestion class to store the potential answer choices, I can make the program display the potential answer choices by including them in the questionText as following in the QuizDriver class
Question x;
x = new MultipleChoiceQuestion("What is the color of the car\na.Red\nb.Green", "a. Red", 3);
t.addQuestion(x); I don't know how to allow the client to construct the list of answer choices one at a time(add one potential answer choice by calling the addAsnwerChoices() method once)
Here are a few original sentences of my assignment which describe what I should do with the MultipleChoiceQuestion class
Using TrueFalseQuestion as a model, develop a new MultipleChoiceQuestion class that can be used to represent a problem where the user must select one of several answer choices (e.g., "Select answer (a), (b), (c), or (d)."). This new question type should have all of the same externally-visible functionality as TrueFalseQuestion, except that it must:
maintain a list of potential answer choices
provide a method that allows the client to construct the list of answer choices one at a time (i.e., the client should be able to call an addAnswerChoice() method to pass a new answer option to the MultipleChoiceQuestion.)
display (as part of the question text) the list of answer choices with appropriate letters ("abcd" instead of "0123") I don't understand what these sentences mean.
1. "Maintain a list of potential answer choices"-- this reminds me of the getPossibleAnswerChoice() method in the TrueFalseQuestion class
public String[] getPossibleAnswerChoice ()
 String[] possibleAnswerChoice = {"true", "false"};
 return possibleAnswerChoice;
 }I wonder that if the potential answer choices I have to store in the MultipleChoiceQuestion class are only letters "a", "b", "c", "d", etc, or include the answer text coming after the letters(eg. a.Red, b.Green)
2. "provide a method that allows the client to construct the list of answer choices one at a time". How do I achieve the functionality "one at a time"? Do I need to pass the input of the client (a potential answer choice) to the variable of the method which stores the list of potential answers?
3. "display (as part of the question text) the list of answer choices with appropriate letters". My question here is that: When the client type in one possible answer, should I append it to the variable questionText? (So I use the questionText variable in the methods of the first and second steps)
Thank you very much for your nice help!
Edited by: Terry001 on Apr 21, 2008 8:01 AM

A question about Object Class

I got a question about Object class in AS3 recently.
I typed some testing codes as following:
var cls:Class = Object;
var cst:* = Object.prototype.constructor;
trace( cls === cst); // true
so cls & cst are the same thing ( the Object ).
var obj:Object = new Object();
var cst2:* = obj.constructor.constructor;
var cst3:* = obj.constructor.constructor.c.constructor;
var cst5:* = Object.prototype.constructoronstructor;
var cst4:* = Object.prototype.constructor.constructor.constructor;
var cst6:* = cls.constructor;
trace(cst2 === cst3 && cst3 === cst4 && cst4 === cst5 && cst5 === cst6); //true
trace( cst == cst2) // false
I debugged into these codes and found that cst & cst2 had the same content but not the same object,
so why cst & cst2 don't point to the same object?
Also, I can create an object by
" var obj:Object = new cst();"
but
" var obj:Object = new cst2();"
throws an exception said that cst2 is not a constructor.
Anyone can help? many thanks!

I used "describeType" and found that "cst2" is actually "Class" class.
So,
trace(cst2 === Class); // true
That's what I want to know, Thank you.

A question about non-static inner class...

hello everybody. i have a question about the non-static inner class. following is a block of codes:
i can declare and have a handle of a non-static inner class, like this : Inner0.HaveValue hv = inn.getHandle( 100 );
but why cannot i create an object of that non-static inner class by calling its constructor? like this : Inner0.HaveValue hv = Inner0.HaveValue( 100 );
is it true that "you can never CREATE an object of a non-static inner class( an object of Inner0.HaveValue ) without an object of the outer class( an object of Inner0 )"??
does the object "hv" in this program belong to the object of its outer class( that is : "inn" )? if "inn" is destroyed by the gc, can "hv" continue to exist?
thanks a lot. I am a foreigner and my english is not very pure. I hope that i have expressed my idea clearly.
// -------------- the codes -------------------
import java.util.*;
public class Inner0 {
// definition of an inner class HaveValue...
private class HaveValue {
private int itsVal;
public int getValue() {
return itsVal;
public HaveValue( int i ) {
itsVal = i;
// create an object of the inner class by calling this function ...
public HaveValue getHandle( int i ) {
return new HaveValue( i );
public static void main( String[] args ) {
Inner0 inn = new Inner0();
Inner0.HaveValue hv = inn.getHandle( 100 );
System.out.println( "i can create an inner class object." );
System.out.println( "i can also get its value : " + hv.getValue() );
return;
// -------------- end of the codes --------------

when you want to create an object of a non-static inner class, you have to have a reference of the enclosing class.
You can create an instance of the inner class as:
outer.inner oi = new outer().new inner();

Questions about your new HP Products? HP Expert Day: January 14th, 2015

Thank you for coming to Expert Day! The event has now concluded.
To find out about future events, please visit this page.
On behalf of the Experts, I would like to thank you for coming to the Forum to connect with us. We hope you will return to the boards to share your experiences, both good and bad.
We will be holding more of these Expert Days on different topics in the months to come. We hope to see you then!
If you still have questions to ask, feel free to post them on the Forum – we always have experts online to help you out.
So, what is HP Expert Day?
Expert Day is an online event when HP employees join our Support Forums to answer questions about your HP products. And it’s FREE.
Ok, how do I get started?
It’s easy. Come out to the HP Support Forums, post your question, and wait for a response! We’ll have experts online covering our Notebook boards, Desktop boards, Tablet boards, and Printer and all-in-one boards.
We’ll also be covering the commercial products on the HP Enterprise Business Community. We’ll have experts online covering select boards on the Printing and Digital Imaging and Desktops and Workstations categories.
What if I need more information?
For more information and a complete schedule of previous events, check out this post on the forums.
Is Expert Day an English-only event?
No. This time we’ll have experts and volunteers online across the globe, answering questions on the English, Simplified Chinese, and Korean forums. Here’s the information:
Enterprise Business Forum: January 14th 7:00am to 12:00pm and 6:00pm to 11:00pm Pacific Time
Korean Forum: January 15th 10am to 6pm Korea Time
Simplified Chinese Forum: January 15th 10am to 6pm China Time
Looking forward to seeing you on January 14th!
I am an HP employee.

My HP, purchased in June 2012, died on Saturday. I was working in recently installed Photoshop, walked away from my computer to answer the phone and when I came back the screen was blank. When I turned it on, I got a Windows Error Recovery message. The computer was locked and wouldn't let me move the arrow keys up or down and hitting f8 didn't do anything.
I'm not happy with HP. Any suggestions?

Have questions about your Creative Cloud or Subscription Membership?

You can find answers to several questions regarding membership to our subscription services. Please see Membership troubleshooting | Creative Cloud - http://helpx.adobe.com/x-productkb/policy-pricing/membership-subscription-troubleshooting- creative-cloud.html for additional information. You can find information on such topics as:
I need help completeing my new purchase or upgrade.
I want to change the credit card on my account.
I have a question about my membership price or statement charges.
I want to change my membership: upgrade, renew, or restart.
I want to cancel my membership.
How do I access my account information or change update notifications?

Branching to new discussion.
Christym16625842 you are welcome to utilize the process listed in Creative Cloud Help | Install, update, or uninstall apps to install and evaluate the applications included with a Creative Cloud Membership. The software is fully supported on recent Mac computers. You can find the system requirements for the Creative Cloud at System requirements | Creative Cloud.

Questions about using the Voice Memos app

I'm currently an Android user, but will be getting an iPhone 6 soon. My most used app is the voice memos app on my Android phone. I have a couple questions about the iPhone's built-in voice memos app.
-Am I able to transfer my voice memos from my Android phone to my iPhone, so my recordings from my Android app will show up in the iPhone's voice memos app?
-When exporting voice memos from the iPhone to computer, are recordings in MP3 format? If not, what format are they in?
-In your opinion, how is the recording quality of the voice memos app?

You cannot import your Android voice memos to your iPhone's voice memo app. You might be able to play the Android memos and have the iPhone pick up the audio and record it.
Here is the writeup about sending voice memos from the iPhone to your computer (from the iPhone User Guide):
App quality is excellent.

Re: Question about the Satellite P300-18Z

Hello everyone,
I have a couple of questions about the Satellite P300-18Z.
What "video out" does this laptop have? (DVI, s-video or d-sub)
Can I link the laptop up to a LCD-TV and watch movies on a resolution of 1080p? (full-HD)
What is the warranty on this laptop?

Hello
According the notebook specification Satellite P300-18Z has follow interfaces:
DVI - No DVI port available
HDMI - HDMI-out (HDMI out port available)
Headphone Jack - External Headphone Jack (Stereo) available
.link - iLink (Firewire) port available
Line in Jack - No Line in Jack port available
Line out Jack - No Line Out Jack available
Microphone Jack - External Micrphone Jack
TV-out - port available (S-Video port)
VGA - VGA (External monitor port RGB port)
Also you can connect it to your LCD TV using HDMI cable.
Warranty is country specific and clarifies this with your local dealer but I know that all Toshiba products have 1 year standard warranty and also 1 year international warranty. you can of course expand it.

Some questions about Muse

First of all, I would like to say that I am very impressed with how well Muse works and how easy it was to create a website that satisfies me. Before I started a daily updated website I thought I would encounter many problems I will not be able to solve. I have only had a few minor issues which I would like to share with you.
The most problems I have with a horizontal layouts (http://www.leftlane.pl/sty14/dig-t-r-3-cylindrowy-silnik-nissana-o-wadze-40-kg-i-mocy-400- km.html). Marking and copying of a text is possible only on the last (top) layer of a document. The same situation is with widgets or anything connected with rollover state - it does not work. In the above example it would be perfect to use a composition/tooltip widget on the first page. Unfortunately, you cannot even move the cursor into it.
It would be helpful to have an option of rolling a mouse to an anchor (like in here http://www.play.pl/super-smartfony/lg-nexus-5.html and here http://www.thepetedesign.com/demos/onepage_scroll_demo.html). I mean any action of a mouse wheel would make a move to another anchor/screen. It would make navigation of my site very easy.
Is it possible to create a widget with a function next anchor/previous anchor? Currently, in the menu every button must be connected to a different anchor for the menu to be functional.
A question about Adobe Muse. Is it possible to create panels in different columns? It would make it easier to go through all the sophisticated program functions.
The hits from Facebook have sometimes very long links, eg.
(http://www.leftlane.pl/sty14/mclaren-p1-nowy-krol-nurburgring.html?fb_action_ids=143235557 3667782&fb_action_types=og.likes&fb_source=aggregation&fb_aggregation_id=288381481237582). If such a link is activated, the anchors in the menu do not work on any page. I mean the backlight of an active state, which helps the user to find out where on page they currently are. The problem also occurs when in the name of a html file polish fonts exist. And sometimes the dots does not work without any reason, mostly in the main page, sometimes in the cooperation page either (http://www.leftlane.pl/wspolpraca/). In the first case (on main page), I do not know why. I have checked if they did not drop into a state button by accident, moved them among the layers, numbered them from scratch and it did not help. In the cooperation page, the first anchor does not work if it is in Y axle set at 0. If I move it right direction- everything is ok.
The text frame with background fill does not change text color in overlay state (http://www.leftlane.pl/sty14/nowe-mini-krolestwo-silnikow-3-cylindrowych.html). I mean a source button at the beginning of every text. I would like a dark text and a light layer in a rollover, but the text after export and moving cursor into it does not change color for some reason.
I was not sure whether to keep everything (whole website) in one Muse file (but I may be mistaken?). I have decided to divide it into months. Everyone is in a different Muse file. If something goes wrong, I will not have any trouble with an upload of a whole site, which is going to get bigger and bigger.
The problem is that every file has two master pages. Everything works well up to the moment when I realize how many times I have to make changes in upper menu when I need to add something there. I have already 5 files, every with 2 masters. Is there any way to solve this problem? Maybe something to do with Business Catalyst, where I could connect a menu to every subpage independently, deleting it from Muse file? Doing so I would be able to edit it everywhere from one place. It would make my work much easier, but I have no idea jendak how to do it.
The comments Disqus do not load, especially at horizontal layouts (http://www.leftlane.pl/sty14/2014-infiniti-q50-eau-rouge-concept.html). I have exchanged some mails and screenshots with Disqus help. I have sent them a screenshot where the comments are not loaded, because they almost never load. They have replied that it works at their place even with attached screenshot. I have a hard time to discuss it, because it does not work with me and with my friends either. Maybe you could fix it? I would not like to end up with awful facebook comments ;). The problem is with Firefox on PC and Mac. Chrome, Safari and Opera work ok.
YouTube movie level layouts do not work well with IE11 and Safari 7 (http://www.leftlane.pl/sty14/wypadki-drogowe--004.html). The background should roll left, but in the above mentioned browsers it jumps up. Moreover the scrolling with menu dots is not fluent on Firefox, but I guess it is due to Firefox issues? The same layout but in vertical version rolls fluently in Firefox (http://www.leftlane.pl/sty14/polskie-wypadki--005.html).
Now, viewing the website on new smartphones and tablets. I know it is not a mobile/tablet layout, but I tried to make it possible to be used on mobile hardware with HD (1280) display. I mean most of all horizontal layouts (http://www.leftlane.pl/sty14/2015-hyundai-genesis.html), where If we want to roll left, we need to roll down. Is there a way to make it possible to move the finger the direction in which the layout goes?
On Android phones (Nexus 4, Android 4.4.2, Chrome 32) the fade away background effect does not work, although I have spent a lot of time over it (http://www.leftlane.pl/lut14/koniec-produkcji-elektrycznego-renault-fluence-ze!.html). It is ok on PC, but on the phone it does not look good. A whole picture moves from a lower layer instead of an edge which spoils everything.
This layout does not look good on Android (http://www.leftlane.pl/sty14/nowe-mini-krolestwo-silnikow-3-cylindrowych.html#a07). The background does not fill the whole width of a page. There are also problems with a photo gallery, where full screen pictures should fill more of a screen.
Is it possible to make an option of scroll effects/motions for a fullscreen slideshow widget thumbnails (http://www.leftlane.pl/sty14/2014-chevrolet-ss%2c-rodzinny-sedan-z-415-konnym-v8.html#a06)? It would help me with designing layouts. Currently, it can go from a bottom of a page at x1 speed or emerge (like in this layout) by changing opacity. Something more will be needed, I suppose.
Sometimes the pictures from gallery (http://www.leftlane.pl/sty14/2014-chevrolet-ss%2c-rodzinny-sedan-z-415-konnym-v8.html#a06 download very slowly. The website is hosted at Business Catalyst. I cannot state when exactly it happens, most of the time it works ok.
I really like layouts like this (http://www.leftlane.pl/sty14/2014-chevrolet-ss%2c-rodzinny-sedan-z-415-konnym-v8.html#a03). On the top is a description and a main text, and the picture is a filled object with a hold set at the bottom edge. That is why there is a nice effect of a filling a whole screen- nevertheless the resolution that is set. It works perfect on PC, but on Android the picture goes beyond the screen. You can do something about it?
In horizontal layouts (http://www.leftlane.pl/sty14/dig-t-r-3-cylindrowy-silnik-nissana-o-wadze-40-kg-i-mocy-400- km.html) holding of a filling object does not work. Everything is always held to upper edge of a screen regardless the settings. Possibility of holding the picture to the bottom edge or center would make my work much easier.
According to UE regulations we have to inform about the cookies. I do not know how to do it in Muse. I mean, when the message shows up one time and is accepted, there would be no need to show it again and again during another visit on the website. Is there any way to do it? Is there any widget for it maybe?
The YouTube widget sometimes changes size just like that. It is so when the miniature of the movie does not load, and the widget is set to stroke (in our case 4 pixels, rounded to 1 pixel). As I remember ( in case of a load error) it extends for 8 pixels wide.
Last but not least - we use the cheapest hosting plan in Business Catalyst. The monthly bandwidth is enough, although we have a lot of pictures and we worried about it at first. Yet we are running out of the disk storage very quickly. We have used more than a half of a 1 GB after a month. We do not want to change BC for a different one, because we like the way it is connected with Muse. But we do not want to buy the most expensive package - but only this one has more disk space. We do not need any other of these functions and it would devastate our budget. Do we have any other option?
I’m using Adobe Muse 7.2 on OS X 10.9.1.
and I'm sending Muse file to <[email protected]>

Unfortunatley, there is no way to get a code view in Muse. I know quite a few people requested it in the previous forum, but not really sure where that ended up. Also, you may not want to bring the html into DW unless you only have 1 or 2 small changes 2 make. Two reasons. First, it isnt backwards compatible, so if you are planning on updating that site in Muse, you will need to make those changes in DW everytime you update. Second, by all accounts the HTML that Muse puts out is not pretty or easy to work with. Unlike you, I am code averse, but there was a lenghty discussion on the previous forum on this topic. I know they were striving to make it better with every release, just not sure where it is at this point.
Dont think I am reading that second question right, but there was a ton of info on that old site. You may want to take a look there, people posted a ton of great unique solutions, so it worth a look.
Here is the link to the old forums- http://support.muse.adobe.com/muse

HT201303 hi just got my new apple ipod touch i need to update my security information other wise it wont let me download apps it says to enter three questions about myself and i get to the third question and it wont let me enter the third question

hi just got my new apple ipod touch and to download apps it wants to add questions about myself for more sercurity information. i get up to question 3 and it wont let me select a question but it will let me write an answer so i just pressed done and then it says i cant carry on because ive mised out information when it wont let me do a question!

Welcome to the Apple community.
You might try to see if you can change your security questions. Start here, change your country if necessary and go to manage your account > Password and Security.
I'm able to do this, others say they need to input answers to their current security questions in order to make changes, I'm inclined to think its worth a try, you don't have anything to lose.
If that doesn't help you might try contacting Apple through Express Lane (select your country, navigate to iCloud help and enter the serial number of one of your devices)

Just installed iOS6, questions about "iMessage" and other things...

I've been a satisfied iOS4 user since I bought my iPhone4, but I was forced to install iOS6 tonight in order to download a "free" app. I found a few new icons on the screen along with about 200 percent more "Settings" I'd like to ask some questions about. I'm sure a few of these could be answered by doing a frantic and thorough search through weeks of posts but I'm a little short on time right now.
First, what exactly is iMessage? Looking at the page for it, I can't see any difference between it and regular text messages. The info page says its to avoid charges, but between my data plan and not being charged for text I don't see where theres any other benefit. The one person I text with the most recently asked me why I had not installed iMessage yet, and didn't have an answer when I asked him why I should. I guess he just wanted to see text replies in blue instead of green.
In a related bit, flipping through Settings>Messages>Send & Receive I find a "2 addresses" section, with my phone number in there as well as my email under "You can be reached by iMessage at:" and "Start new conversations from:". What good does it do iMessages to have my email address? Does the Mail app handle text as well as email addresses? That seems to be the only explanation, and also very odd to think I'd be trying to text through my Mail app.
Second, looking through the Settings>Mail I see now that I have an icloud email address as well as the mac.com address I've been desperately hanging on to for the past 10 years, and the me.com address they've been trying to force me into since those came out. (I was happy to see I could delete the me.com address from the phone. I wish I could delete it from the universe.)
I wasn't even aware there was a such thing as icloud.com addresses. When did this happen? What is it used for?
Third, under that icloud Setting I see a long list of apps with buttons labeled "Off" under it. What are those for? Under the Mac.com settings I see switches for "Mail" and "Notes", with Mail on and Notes off. The Notes app (which I haven't used since my old iPhone 3) still opens, regardless of this setting.
Fourth, I now have an item called "Facetime" under my Settings. It is off, but underneath it says "Your phone number and/or email address will be shared with people you call". I understand caller ID normally sends caller number info to the receiver, but why would someone need my email address if I call them?
Fifth, I now have a "Music" setting, at the bottom of which I see a "Home Sharing" item, which when clicked brings up my AppleID and asks me if I want to Sign Out or Cancel. What is Home Sharing? Its also at the bottom of the "Video" settings.
Sixth, now I have Twitter and Facebook settings? For what? I don't have accounts with either of those companies. So why have settings, especially since it asks me to create accounts and download apps for those companies right in the Settings?
Seventh, there is a camera icon on the unlock screen. Touching it causes the screen to bounce up about a quarter inch, almost but not quite revealing something behind it. I should probably just quit asking about this stuff already, but I'll take the bait - what is this now?
Finally, what is the Notification Center used for?
If I got a text under iOS4, it would put an alert on the Unlock screen. Scrolling through this huge list of things under the Notification settings I'm really blown away by all the apps set up to yell at me. I can see having an alert for a text message but Game Center? What the heck is that, and why is it set up to hit me with a "Badge App Icon" (whatever that is) when I get alerts from "Everyone". Similarly, the phone is set to alert me to something called a "Photostream Alert"? What is this? Why is there a Phone section for the Notification Center? So they can put a Notice on my screen to tell me the phone is ringing? Holy cow! The phone is set to send me alerts from the "Weather Widget". So if I miss the fact its raining there will be a message on my screen to let me know? Whats next - a buzzer to tell me I'm listening to music?
There's a lot more, like what would I need Passbook for when I have the actual movie tickets, gate boarding passes, coupons, etc in my hands, but we'll leave that for another time. Many thanks to all who can offer some answers to my questions above.

Hey Taantumus!
Here is an article that will provide some guidance on this question:
Apple ID: Changing your password
http://support.apple.com/kb/ht5624
The next time you use an Apple feature or service that uses Apple ID, you'll be asked to sign in with your new Apple ID password.
Thanks for coming to the Apple Support Communities!
Regards,
Braden

Questions about using Bitlocker without TPM

We currently use Bitlocker to encrypt our Windows 7 computers with TPM. Now we are looking at encrypting some Windows 7 computers without a TPM. I see how to change the group policy setting to allow Bitlocker without a TPM. I have looked at a lot of other
threads and I have a few questions about how the Bitlocker without TPM works.
1) I see a USB drive containing a key is required for Bitlocker configurations without a TPM, say the end user loses this USB drive, what are the recovery options for their computer?
This article seems to indicate that without the USB drive connected, you are unable to even access recovery options http://blogs.technet.com/b/hugofe/archive/2010/10/29/bitlocker-without-tpm.aspx
We have recovery backed up to AD when Bitlocker is enabled, but how could we do this recovery on a computer on computer where it's USB is lost? Would we have to remove the HD itself and attach it to another computer to access?
2) After enabling Bitlocker on a computer without a TPM and using the USB Drive for the key, is there a way to also add a PIN or password protection at bootup?

Hi,
Sorry for my dilatory reply,
Configuring a startup key is another method to enable a higher level of security with the TPM. The startup key is a key stored on a USB flash drive, and the USB flash drive must be inserted every time the computer starts. The startup key is used to provide
another factor of authentication in conjunction with TPM authentication. To use a USB flash drive as a startup key, the USB flash drive must be formatted by using the NTFS, FAT, or FAT32 file system.
You must have a startup key to use BitLocker on a non-TPM computer.
From: http://technet.microsoft.com/de-de/library/ee449438(v=ws.10).aspx#BKMK_Key
For more Q&A about BitLocker, you can refer to the link above.
hope this is helpful.
Roger Lu
TechNet Community Support

Questions about Rooting...

Hi everyone, I’ve some questions about rooting my Xperia Arc S. Hopefully I’ll get helpful answers from you.
If I root my phone, shall I get regular software official updates from Sony?
Currently Sony is rolling out the ICS update. After rooting the phone am I able to upgrade my phone to ICS?
While rooting the phone if any damage is done, can that be recoverable by installing a fresh OS or something?
Does the rooting process delete all the existing contacts, messages, apps etc?
Finally can anyone please provide a full proof guide/tutorial for rooting the Xperia Arc S?
Thanks in advance.
Solved!
Go to Solution.

Do you have an app named Super USer ?
Were you on 4.0.4 and then rooted your mobile using this method ?
If yes then your mobile is not rooted for sure
See how to root 4.0.4 here
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