A question about subclasses of visibility

Hello,
I read a book named Learning Java it say
"as you override methods in a subclass, the overriding method must be at least as visible as the overridden method.While it is possible to take a private method and override it with a public method in a subclass, the reverse is not possible."
But I don't get it.
Does somebody know the reason?
Thanks.

This is a fairly common question.. search the forums first, and post back here if you still have any questions.

Similar Messages

Quick question about subclasses in swing

When you create a subclass of JFrame or JPanel, should you put super() in the constructor? It doesn't seem to make a difference either way.

I never do it ...
When you create new child classes, the parent classes constructors are called automatically.
public class Inheritance {
    public static void main(String[] args) {
        new Child();
class Parent{
    public Parent(){
        System.out.println("This is Parent");
class Child extends Parent{
    public Child(){
        System.out.println("This is Child");
Output
This is Parent
This is Child
*/

Question about the programming of a legend

Hello everybody,
I have a question about the programming of a waveform's legend. I
already asked here in this forum about the legend programming (03)
months ago.
I went satisfied but I ve just noticed that this code
(See Code old_legend_test.llb with main.vi as main function) operates a
little different from my expectances.
Therefore I have a new question and I want to know if it
is possible by labview programming to plot and show, on a waveform
chart, a signal with activ plot superior to zero (0) without to be
obliged to plot and show a signal with activ plot equal to zero (0) or
inferior to the desired activ plot.
I give you an example
of what I m meaning. I have by example 4 signals (Signal 0, 1, 2 and 3)
and each signal corresponds respectively to a channel (Chan1, Chan2,
Chan3, Chan4). I want to control the legend (activ plot, plot name and
plot color) programmatically. Is it possible with labview to plot signal
1 or 2 or 3 or (1, 3) or (2,3) or (1,2,3) or other possible combination
without to active the signal with the corresponding activ plot zero
(0)?
Let see the labview attached data
(new_legend_test.llb with main.vi as main function). When I try to
control the input selected values again I get them back but I don't
understand why they have no effect on the legend of my waveform chart.
Could somebody explain me what I m doing wrong or show me how to get a
correct legend with desired plots? Thank by advance for your assistance.
N.B.
The
both attached data are saved with labview 2009.
Sincerly,PrinceJack
Attachments:
old_legend_test.llb ‏65 KB
new_legend_test.llb ‏65 KB

Hi
princejack,
Thanks for
posting on National Instruments forum.
The behavior
you have is completely normal. You can control the number of row displayed in
the legend and this rows are linked to the data you send to your graph. Thus,
if you have 3 arrays of data, let say chan1, chan2 and chan3, you can choose
which data you want to display in your graph using the property node (Active
plot and visible). But for the legend as you send 3 plots there is an array of
the plot name [chan1, chan2, chan3] and you can display 0, 1, 2 or 3 rows of
this array but you cannot control the order in this array! So, to be able to
change this array you have to only send data you need to you graph. I'm not
sure my explanations are clear so I have implemented a simple example doing
that.
Benjamin R.
R&D Software Development Manager
http://www.fluigent.com/
Attachments:
GraphLegend.vi ‏85 KB

Question about size of ints in Xcode

Hello. I have a a few quick questions about declaring and defining variables and about their size and so forth. The book I'm reading at the moment, "Learn C on the Mac", says the following in reference to the difference between declaring and defining a variable:
A variable declaration is any statement that specifies a variables name and type. The line *int myInt;* certainly does that. A variable definition is a declaration that causes memory to be allocated for the variable. Since the previous statement does cause memory to be allocated for myInt, it does qualify as a definition.
I always thought a definition of a variable was a statement that assigned a value to a variable. If a basic declaration like "int myInt;" does allocate memory for the variable and therefore is a definition, can anyone give me an example of a declaration that does not allocate memory for the variable and therefore is not a definition?
The book goes on, a page or so late, to say this:
Since myInt was declared to be of type int, and since Xcode is currently set to use 4-byte ints, 4 bytes of memory were reserved for myInt. Since we haven't placed a value in those 4 bytes yet, they could contain any value at all. Some compilers place a value of 0 in a newly allocated variable, but others do not. The key is not to depend on a variable being preset to some specific value. If you want a variable to contain a specific value, assign the value to the variable yourself.
First, I know that an int can be different sizes (either 4 bytes or 8 bytes, I think), but what does this depend on? I thought it depended on the compiler, but the above quote makes it sound like it depends on the IDE, Xcode. Which is it?
Second, it said that Xcode is currently set to use 4-byte ints. Does this mean that there is a setting that the user can change to make ints a different size (like 8 bytes), or does it mean that the creators of Xcode currently have it set to use 4-byte ints?
Third, for the part about some compilers giving a newly allocated variable a value of 0, does this apply to Xcode or any of its compilers? I assume not, but I wanted to check.
Thanks for all the help, and have a great weekend!

Tron55555 wrote:
I always thought a definition of a variable was a statement that assigned a value to a variable. If a basic declaration like "int myInt;" does allocate memory for the variable and therefore is a definition, can anyone give me an example of a declaration that does not allocate memory for the variable and therefore is not a definition?
I always like to think of a "declaration" to be something that makes no changes to the actual code, but just provides visibility so that compilation and/or linking will succeed. The "definition" allocates space.
You can declare a function to establish it in the namespace for the compiler to find but the linker needs an actual definition somewhere to link against. With a variable, you could also declare a variable as "extern int myvar;". The actual definition "int myvar;" would be somewhere else.
According to that book, both "extern int myvar;" and "int myvar;" are declarations, but only the latter is a definition. That is a valid way to look at it. Both statements 'delcare' something to the compiler, but on the second one 'define's some actual data.
First, I know that an int can be different sizes (either 4 bytes or 8 bytes, I think), but what does this depend on? I thought it depended on the compiler, but the above quote makes it sound like it depends on the IDE, Xcode. Which is it?
An "int" is supposed to be a processor's "native" size and the most efficient data type to use. A compiler may or may not be able to change that, depending on the target and the compiler. If a compiler supports that option and Xcode supports that compiler and that option, then Xcode can control it, via the compiler.
Second, it said that Xcode is currently set to use 4-byte ints. Does this mean that there is a setting that the user can change to make ints a different size (like 8 bytes), or does it mean that the creators of Xcode currently have it set to use 4-byte ints?
I think that "setting" is just not specifying any option to explicitly set the size. You can use "-m32" or "-m64" to control this, but I wouldn't recommend it. Let Xcode handle those low-level details.
Third, for the part about some compilers giving a newly allocated variable a value of 0, does this apply to Xcode or any of its compilers? I assume not, but I wanted to check.
I don't know for sure. Why would you ask? Are you thinking of including 45 lines of macro declarations 3 levels deep to initialize values based on whether or not a particular compiler/target supports automatic initialization? Xcode current supports GCC 3.3, GCC 4.0, GCC 4.2, LLVM GCC, CLang, and Intel's compiler for building PPC, i386, and x86_64 code in both debug and release, with a large number of optimization options. It doesn't matter what compiler you use or what it's behavior is - initialize your variables in C.

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

Question about privacy in Java

hi, i have a question about privacy practices in Java. I always thought it was bad form to program with too many global variable. However, when I program in Java i find that most of the time I am making my variables global. Is the fact that they are in a class supposed to make up for that fact? With subclasses you can also have 3rd parties working on your data. It seems a bit suspicious to me, like the data should be maintained more strictly, or is it my job to do that? I am just curious, but it seems java promotes global variables, which I find to be bad programming practice since anything can operate on them. I appreciate any input...

However, when I program in Java
i find that most of the time I am making my variables
global. (meaning public)Sounds like you are writing bad code. Public variables should be extrememly rare except static final 'constants'.
Is the fact that they are in a class supposed
to make up for that fact? Absolutely not.
With subclasses you can also
have 3rd parties working on your data. It seems a bit
suspicious to me, like the data should be maintained
more strictly, or is it my job to do that? Yes, it's your job.
I am just
curious, but it seems java promotes global variables,
which I find to be bad programming practice since
anything can operate on them. I appreciate any
input...Java does not promote public variables. You have to explicitly make them public.

Some question about fade in // fade out by hideEffect and showEffect in Actionscript

Some question about fade in // fade out by hideEffect and
showEffect in Actionscript
Please kindly take a look at the following page:
http://camusmiu.no-ip.com/HounganQuestion/PictureHolderTest.html
(can view source)
I tried to make an image preloaded and scale the image to
it's preferred size.
When I came to consolidate the stuff into a component, I
found the application goes weird as I implementation the show/hide
effect.
The third trial which just hide and show the images directly,
instead of using viewstack, fail to bring the second image onto
screen.
It just used fadeOut instead of fadeIn(you see there is a
flash of the second image)
After some study of showEffect and hideEffect behaviour,
seems the mechanism of hide/show a component works in this way:
this._fadeIn:Fade = new Fade();
this._fadeIn.alphaFrom = 0;
this._fadeIn.alphaTo = 1;
this._fadeIn.duration = 1000;
this._fadeOut:Fade = new Fade();
this._fadeOut.alphaFrom = 1;
this._fadeOut.alphaTo = 0;
this._fadeOut.duration = 1000;
Component_A.visible = true;
Component_A.setStyle("showEffect", this._fadeIn);
Component_A.setStyle("hideEffect", this._fadeOut);
then when I set Component_A.visible = false, the sequence
works like following:
Component_A.visible = true
Component_A.visible = true, alpha = 100;
Component_A.visible = true, alpha = 50;
Component_A.visible = true, alpha = 0;
Component_A.visible = false;
The above sequence works visa versa as:
Component_A.visible = false;
Component_A.visible = true, alpha = 0;
Component_A.visible = true, alpha = 50;
Component_A.visible = true, alpha = 100;
Component_A.visible = true;
(Correct me if i am wrong)
========================================================================================== ====
From what I observe from the application, I have two
question.
1) When more than one component using the this._fadeIn,
this_fadeOut as the hide/show effects, the component in instance of
this._fadeIn? will it mess out if more than one component using the
fadeIn instance in the same time?
2) from the third component, i.e. PictureHolder3, when I load
other the picture , it fade out the new image instead of fading
in... Seems there is problem if I hide show too frequent. I think
when I hide then show right the way, the component only do the hide
part...
Can someone pls look into it and tell me what I did wrong?
Cuz in normal practice I don't think appropriate to use ViewStack
in Actionscript...

Hello Jack,
Currently, you can only import an swf file or you can embed videos from youtube, vimeo etc. into Muse / add HTML5 Video to Your Website.
Take a look at these simple videos that explain the currently available processes for adding videos in Muse, in a step by step method:
1. http://tv.adobe.com/watch/learn-adobe-muse-cc/inserting-a-youtube-flic kr-or-hulu-video/
2. http://www.youtube.com/watch?v=5in4swnIFsw
3. http://www.youtube.com/watch?v=KnBFLQheOk4
Hope this helps.
Cheers
Parikshit

Questions about ActiveX Bridge and SWT

Hi !
I found few weeks ago the www.reallyusefulcomputing.com site answering my question about Java & Macro of MSWord. Now I've found two steps that I am not able to overcome.
First, when I build a simple application and I have internal libraries to use, am I compelled to place the jars in the lib/ext directory of the Java Runtime Directory? I have many difficulties in placing a convenient class-path in the manifest file. Why does the application ignore the manifest string?
The second problem (and the biggest one) is that I am trying to build an SWT java-bean-application but I have problems during runtime. Is it possible to use this technology for my software or am I compelled to use AWT and SWING?
I really hope you can help me.
Thank you in advance.

hi,
I have to catch events from excel sheet in my java code..events like some change in value or a click of some user defined button etc.I have written th follwoing code but it does not gives me any event.It simply opens the specified file in the excel in a seperate window.but when i click on the sheet or change some value no event is captured by my code....can ne one pls tell me how to go about it....
public class EventTry2 {
 private Shell shell;
 private static OleAutomation automation;
 static OleControlSite controlSite;
 protected static final int Activate = 0x00010130;
 protected static final int BeforeDoubleClick = 0x00010601;
 protected static final int BeforRightClick = 0x000105fe;
 protected static final int Calculate = 0x00010117;
 protected static final int Change = 0x00010609;
 protected static final int Deactivate = 0x000105fa;
 protected static final int FollowHyperlink = 0x000105be;
 protected static final int SelectionChange = 0x00010607;
 public void makeVisible()
 Variant[] arguments = new Variant[1];
 arguments[0]=new Variant("true");
 //Visible---true
 automation.setProperty(558,arguments);
 //EnableEvent--true
 boolean b =automation.setProperty(1212,arguments);
 System.out.println(b);
 public Shell open(Display display){
 this.shell=new Shell(display);
 this.shell.setLayout(new FillLayout());
 Menu bar = new Menu(this.shell,SWT.BAR);
 this.shell.setMenuBar(bar);
 OleFrame frame = new OleFrame(shell,SWT.NONE);
 File file= new File("C:\\Book1.xls");
 try{
 controlSite = new OleControlSite(frame, SWT.NONE, "Excel.Application");
 this.shell.layout();
 boolean a2=true;
 a2=(controlSite.doVerb(OLE.OLEIVERB_SHOW|OLE.OLEIVERB_OPEN|OLE.OLEIVERB_UIACTIVATE|OLE.OLEIVERB_HIDE|OLE.OLEIVERB_PROPERTIES|OLE.OLEIVERB_INPLACEACTIVATE)== OLE.S_OK);
 System.out.println("Activated::\t"+a2);
 }catch(SWTException ex)
 System.out.println(ex.getMessage());
 return null;
 automation = new OleAutomation(controlSite);
 //make the application visible
 makeVisible();
 System.out.println("Going to create Event listener");
 OleListener eventListener=new OleListener(){
 public void handleEvent(OleEvent event){
 System.out.println("EVENT TYPE==\t"+event.type);
 switch(event.type){
 case Activate:{
 System.out.println("Activate Event");
 case BeforeDoubleClick:{
 System.out.println("BeforeDoubleClick Event");
 case BeforRightClick:{
 System.out.println("BeforeRightClick Event");
 case Calculate:{
 System.out.println("Calculate Event");
 case Change:{
 System.out.println("Change Event");
 case Deactivate:{
 System.out.println("DeActivate Event");
 case FollowHyperlink:{
 System.out.println("Activate Event");
 case SelectionChange:{
 System.out.println("Activate Event");
 Variant[] arguments = event.arguments;
 for(int i=0;i<arguments.length;i++)
 System.out.println("@@");
 arguments.dispose();
 System.out.println("outside");
 OleAutomation sheetAutomation=this.openFile("C:\\Book1.xls");
 controlSite.addEventListener(sheetAutomation,Activate,eventListener);
 controlSite.addEventListener(sheetAutomation,BeforeDoubleClick,eventListener);
 controlSite.addEventListener(sheetAutomation,BeforRightClick,eventListener);
 controlSite.addEventListener(sheetAutomation,Calculate,eventListener);
 controlSite.addEventListener(sheetAutomation,Change,eventListener);
 controlSite.addEventListener(sheetAutomation,Deactivate,eventListener);
 controlSite.addEventListener(sheetAutomation,FollowHyperlink,eventListener);
 controlSite.addEventListener(sheetAutomation,SelectionChange,eventListener);
 shell.open();
 return shell;
 public OleAutomation openFile(String fileName)
 Variant workbooks = automation.getProperty(0x0000023c);//get User Defined Workbooks
 Variant[] arguments = new Variant[1];
 arguments[0]= new Variant(fileName);
 System.out.println("workbooks::\t"+workbooks);
 IDispatch p1=workbooks.getDispatch();
 int[] rgdispid = workbooks.getAutomation().getIDsOfNames(new String[]{"Open"});
 int dispIdMember = rgdispid[0];
 Variant workbook = workbooks.getAutomation().invoke( dispIdMember, arguments );
 System.out.println("Opened the Work Book");
 try {
 Thread.sleep(500);
 } catch (InterruptedException e) {
 // TODO Auto-generated catch block
 e.printStackTrace();
 int id = workbook.getAutomation().getIDsOfNames(new String[]{"ActiveSheet"})[0];
 System.out.println(id);
 Variant sheet = workbook.getAutomation().getProperty( id );
 OleAutomation sheetAutomation=sheet.getAutomation();
 return(sheetAutomation);
 * @param args
 public static void main(String[] args) {
 // TODO Auto-generated method stub
 Display display=new Display();
 Shell shell=(new EventTry2()).open(display);
 while(!shell.isDisposed()){
 if(!display.readAndDispatch()){
 display.sleep();
 controlSite.dispose();
 display.dispose();
 System.out.println("-----------------THE END-----------------------------");

Question about child "windows"

Hello Everyone,
First, I want to thank everyone who's so graciously taken
their time to answer my previous questions. Because of you, I am
well on my way to developing my very first real world Flex
application. I am consistently astounded at how helpful this
community is and am very thankful to have you all here.
Now, I do have one question about some code that works on the
example but not in real life. I am trying to open a popup window
from a class named composeScreen. In my CDATA section, I have the
following code:
function showWindow(modal) {
var popup = mx.managers.PopUpManager.createPopUp(this,
composeNewMessage, modal, {deferred: true});
Yet, when I save the program, Flex Builder tells me:
"Access of undefined property mx"
Any idea why this is happening?
I've even tried importing the mx.managers.popUpManager class
and it makes no difference.
Please help! This is driving me nuts!
Thanks in Advance,
Anthony

Hi Anthony,
You will have to use popup manager class for this.Here is the
code to give you a lil bit of direction. Call init() function in
the initilize event of the <mx: application> tag
import mx.managers.PopUpManager;
private function init():void{
myWindow = PopUpManager.createPopUp(this, MyWindow, false);
myWindow.visible = false;
myWindow.x = 200;
myWindow.y = 200;
myWindow.height = 100;
private function showWindow():void{
myWindow.visible = true;
myWindow.expand.play();
<mx:Button id="btn" label="click me"
click="showWindow()"/>
When you click on the button your child window must pop
up.

HOME -LAB Question about Openfiler Datastore

Question about Open filer Data store: Once I did the LUN mapping on open filer via GUI, I could not able to see the paths on Esxi host and the luns are not visible on host while configuring or presenting the data store, as I tried couple of times,no success .Please help how to resolve this issue .
Thank you
Sandy

Did you added iscsi adapter in to your esxi host? if not then add the adapter first and then try to rescan the datastore .
here is the step by step guide to configure openfiler to use with vmware esxi host.
http://techhead.co/how-to-configure-openfiler-v23-iscsi-storage-for-use-with-vmware-esx/

Techie Question about iWeb, outbound links, and Google Analytics

Hi,
I have a kind of pretty technical question about using Google Analytics (GA) with iWeb sites to measure clicks on outbound links. Here's the setup:
1) My website's online, and GA is working properly.
2) I don't sell stuff directly, but I do have a "Purchase" page which contains a link to a specific Amazon page.
3) I'm pretty sure I can measure how many people go to the Purchase page using GA, but how do I measure whether visitors click on the Amazon link? It would be interesting to me to be able to gauge what the conversion rate is; that is, how many people actually proceed to purchase the product at Amazon.
I've checked the GA instructions and there's a page about manually tracking clicks on outbound links but it requires some code inputting. I know zero about coding, but I'm pretty sure that in iWeb you can't get access to the source code to input the required code.
Am I wrong about this? And if I am, then does anyone here know how to measure the clickthrough rate?
Anyway, hope you can help. Thanks in advance.

I don't know about the link tracking but you could have the link take you to a redirect page which automatically sends them to Amazon.com after a preset time, 0 seconds to whatever you'd like. You can put a counter on that redirect page, like StatCounter. StatCounter can tell you how many, from where they came, i.e country and area, repeat visits, etc.
Tutorials #12 & #13 describe how to put a visible counter on a page but with a redirect page you wouldn't have to bother since it wouldn't be seen. You can get all of your information from your account on the StatCounter site.
The redirect page would be a simple plain text page titled redirect.html and would look like this:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="refresh"
content="0; Destination URL">
<title>Redirecting or whatever you'd like to appear at the top of the browser</title>
</head>
<body>
</body>
</html>
0 Is the number of seconds to wait before redirecting the visitor. If set to zero the visitor would not know they were being redirected. Replace Destination URL with the Amazon URL you want them to go to.
OT

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.

A question about subclasses of visibility

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