[RESOLVED] Help with JOptionPane

I'm in the US Marines and stationed in Japan. I'm taking an online Java Programming class (part of my degree curriculum) and am only in week 2. I have the following task:

Quote:

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Write a Java program that reads an integer and checks whether it is even.

If your input is 25, your output should be:

Is 25 even?

false

If your input is 2000, your output should be:

Is 2000 even?

true

Also, the program must check if the number the user entered is between 1 and 1000.

If your input is 25, your output should be:

The number 25 between 1 and 1000 is true.

If your input is 2000, your output should be:

The number 2000 between 1 and 1000 is false.

1.The input and output must use JOptionPane dialog and display boxes.

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My code thus far is:

Code:

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import javax.swing.JOptionPane;

public class NumberChecker {
  public static void main (String args[]) {
      // Prompt the user to enter a number
    String numberString = JOptionPane.showInputDialog(null, "Enter a number:", "Number Checker", JOptionPane.QUESTION_MESSAGE);
               
    //  Convert the string into an int value
    int number = Integer.parseInt(numberString);
                               
    //  Check if the number is even
    int isEven; {
    number = number % 2;
               
    //  Display the result in a message dialog box declaring if it is even or odd
    JOptionPane.showMessageDialog(null, "Is " + number + " an even number?\n> " + isEven, "Number Checker", JOptionPane.INFORMATION_MESSAGE);}
        }
    //  Check if the number is in the prescribed range
    boolean isRange; { 
    return ! ((1 < number) && (number < 1000));
                       
    // Display the result in a message dialog box declaring if it falls in the prescribed range
    JOptionPane.showMessageDialog(null, "Is the number " + number + " between 1 and 1000?\n> " + isRange, "Range Checker", JOptionPane.INFORMATION_MESSAGE);}
    {
    System.exit (0);
    }
}

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My problem is that when I go to compile, I'm receiving errors for the return ! and an error code for my range checker saying that it is looking for a symbol. Can anyone tell me what I'm doing wrong and why?

Thank you in advance!

I downloaded JCreator LE and am trying to clean it up a little.

Here's what I've gotten so far:

Code:

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import javax.swing.JOptionPane;

public class NumberChecker {
        public static void main (String args[]) {
                // Prompt the user to enter a number
                String numberString = JOptionPane.showInputDialog(null, "Enter a number:", "Number Checker", JOptionPane.QUESTION_MESSAGE);

                //  Convert the string into an int value
                int number = Integer.parseInt(numberString);
                int number = range;

                //  Check if the number is even
                int isEven; {
                number = number % 2;

                //  Display the result in a message dialog box declaring if it is even or odd
                JOptionPane.showMessageDialog(null, "Is " + number + " an even number?\n> " + isEven, "Number Checker", JOptionPane.INFORMATION_MESSAGE);}
        }
                //  Check if the number is in the prescribed range
                boolean isRange; {
                        return ! ((1 < range) && (range < 1000));

                // Display the result in a message dialog box declaring if it falls in the prescribed range
                JOptionPane.showMessageDialog(null, "Is the number " + range + " between 1 and 1000?\n> " + isRange, "Range Checker", JOptionPane.INFORMATION_MESSAGE);}
                {
                System.exit (0);
        }
}

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Still getting the errors, however.

Uhh, I would recommend you go through a basic Java tutorial because this is all wonky.

You're not declaring your methods properly and you also don't have any error catching.

Here is a quick example of what you need to do. There are much better ways to do this, but here are the basics.

Code:

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  try{
                 
              // Prompt the user to enter a number
            String numberString = JOptionPane.showInputDialog(null, "Enter a number:", "Number Checker", JOptionPane.QUESTION_MESSAGE);
                       
            //  Convert the string into an int value
            int number = Integer.parseInt(numberString);
                                       
            //  Check if the number is even
            int checkEven = number % 2;
           
            boolean isEven = false;
           
            if (checkEven == 0)
                    isEven = true;
           
            boolean inRange = false;
            if (number < 1000 && number > 1)
                    inRange = true;
                       
            //  Display the result in a message dialog box declaring if it is even or odd
            JOptionPane.showMessageDialog(null, "Is " + number + " an even number?\n> " + isEven, "Number Checker", JOptionPane.INFORMATION_MESSAGE);
                    JOptionPane.showMessageDialog(null, "Is the number " + number + " between 1 and 1000?\n> " + inRange, "Range Checker", JOptionPane.INFORMATION_MESSAGE);
                   
                  }catch(NumberFormatException ne){
                          JOptionPane.showMessageDialog(null, "You must enter an integer.", "Number Format Error", JOptionPane.ERROR_MESSAGE);
                  }catch (Exception e){
                          JOptionPane.showMessageDialog(null, "An Unknown error has occured.","Unknown Error", JOptionPane.ERROR_MESSAGE);
                  }//end try/catch

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The class I'm enrolled in is an Intro to Java, so I guess it's basically a tutorial. :) The book (JAVA: How to Program 7th ed) presents the material in basic syntax that is run from the command line and has input/output there also. The instructor presented a couple of very basic dialog box examples, but the context is a little outside my reasoning so far.

I really appreciate your help. I wasn't aware of the the "checkEven" command and that alone makes a world of difference. I pasted what you presented into my original in JCreator and am still getting a few errors with the error checking that you provided; I'll have to iron that out. I'm sure it's probably declarations on my part again.

Thank you again and have a great day!

Glad to help, but 1 thing: checkEven is a variable, not a method.

Since you were using input %(mod) 2, if it was even it would return 0. So if it was 0, I was telling the program that the number was even.