Question

I have somewhat of a strange problem.

I’m writing a simple Sudoku program. Everything works perfectly now except this method:

public static void checkAnswerKey()
    {
        int rowCounter = 0;
        int columnCounter = 0;

        System.out.println("The answers that are correct are (F is incorrect): ");

        for (rowCounter = 0; rowCounter <= 8; rowCounter += 1)
        {
            for (columnCounter = 0; columnCounter <= 8; columnCounter += 1)
            {
                if (gui.userInputFormattedArray[rowCounter][columnCounter].getText() == io.puzzleAnswerArray[rowCounter][columnCounter].toString())
                {
                    gui.userInputFormattedArray[rowCounter][columnCounter].setBackground(gui.correctAnswer);
                    System.out.print(gui.userInputFormattedArray[rowCounter][columnCounter].getText() + " ");
                }
                else
                {
                    gui.userInputFormattedArray[rowCounter][columnCounter].setBackground(gui.incorrectAnswer);
                    System.out.print(gui.userInputFormattedArray[rowCounter][columnCounter].getText() + io.puzzleAnswerArray[rowCounter][columnCounter].toString() + " ");
                    //System.out.print("F" + " ");
                }
            }
            System.out.println();
        }

This is taken from the game.java file.

Now, this method is supposed to check the user input against the internal answer. Which it does. But everything turns up incorrect.

Here are the declarations/instantiations from the io.java and the gui.java files.

public class gui extends JFrame implements ActionListener{

…

    public static JFormattedTextField[][] userInputFormattedArray = new JFormattedTextField[9][9];
    //Create the container.
    public Container pane = getContentPane();
    //The font the game uses.
    public Font gameFont = new Font("Arial", Font.PLAIN, 30);
    //Correct and incorrect answer colors.
    static Color correctAnswer = new Color(100, 255, 100);
    static Color incorrectAnswer = new Color(255, 100, 100);

These two methods are launched in the constructor:

public void showTextFields()
    {
        int rowCounter = 0;
        int columnCounter = 0;

        for (rowCounter = 0; rowCounter <= 8; rowCounter += 1)
        {
            for (columnCounter = 0; columnCounter <= 8; columnCounter += 1)
            {
                userInputFormattedArray[rowCounter][columnCounter] = new JFormattedTextField();
                pane.add(userInputFormattedArray[rowCounter][columnCounter]);
                userInputFormattedArray[rowCounter][columnCounter].setFont(gameFont);
                userInputFormattedArray[rowCounter][columnCounter].setHorizontalAlignment(JTextField.CENTER);
            }
        }
    }

    public void setTextFields()
    {
        String heldString;
        boolean notEditable = false;
        int rowCounter = 0;
        int columnCounter = 0;

        for (rowCounter = 0; rowCounter <= 8; rowCounter += 1)
        {
            for (columnCounter = 0; columnCounter <= 8; columnCounter += 1)
            {
                if (game.puzzleUserShownArray[rowCounter][columnCounter] != 0)
                {
                    heldString = game.puzzleUserShownArray[rowCounter][columnCounter].toString();
                    userInputFormattedArray[rowCounter][columnCounter].setText(heldString);
                    userInputFormattedArray[rowCounter][columnCounter].setEditable(notEditable);
                }
            }
        }
    }

And this is where the answer comes from:

public static Integer[][] puzzleAnswerArray = new Integer[9][9];

public void getPuzzle() throws FileNotFoundException
    {
        Scanner puzzlesInFile = new Scanner(new FileReader("C:\\Users\\owner\\Desktop\\eclipse\\projects\\Sudoku\\Sudoku\\src\\puzzles.dat"));
        String searchParameter = "#puzzle" + intPuzzleSeed;
        int rowCounter = 0;
        int columnCounter = 0;

        //Prints the search parameter into the console, ensuring accuracy with the RNG.
        System.out.print(searchParameter);
        System.out.println();

        //
        puzzlesInFile.findWithinHorizon(searchParameter, 0);
        while (puzzlesInFile.hasNextInt())
        {
            for (rowCounter = 0; rowCounter <= 8; rowCounter += 1)
            {
                for (columnCounter = 0; columnCounter <= 8; columnCounter += 1)
                {
                    puzzleAnswerArray[rowCounter][columnCounter] = puzzlesInFile.nextInt();
                    System.out.print(puzzleAnswerArray[rowCounter][columnCounter].toString() + " ");
                }
                System.out.println();
            }
        }
        puzzlesInFile.close();
    }

I hope that this is enough info. Am I missing something obvious? Here is the console output from a completed puzzle, by the way:

The answers that are correct are (F is incorrect):
11 22 33 44 55 66 77 88 99
44 55 66 77 88 99 11 22 33
77 88 99 11 22 33 44 55 66
22 33 44 55 66 77 88 99 11
55 66 77 88 99 11 22 33 44
88 99 11 22 33 44 55 66 77
33 44 55 66 77 88 99 11 22
66 77 88 99 11 22 33 44 55
99 11 22 33 44 55 66 77 88

Here is the GUI:

—EDIT:I can’t post the GUI because I have less than 10 reputation. As soon as I get there, I will post a .png of the GUI.—

My guess would be that even though the “strings” are the same, it for some reason or another isn’t recognizing it as the same. Let me know if you need to see more code, but I think I covered everything.

Answer 1

You are using == for string equality check.

if(gui.userInputFormattedArray[rowCounter][columnCounter].getText() == io.puzzleAnswerArray[rowCounter][columnCounter].toString()) {

Use .equals() methods instead. And that applies not just for string but for any kind of objects. In case of objects == checks the identity of the objects.

Try:

if(gui.userInputFormattedArray[rowCounter][columnCounter].getText().equals(io.puzzleAnswerArray[rowCounter][columnCounter].toString())) {