Help Passing Variables

**jo15765** · May 7th, 2012, 03:13 PM

I am running this code below:

	public static void Check(int masterNumber)
	{
	int reverseIt = 0;
 
		for (int i=0; i<=masterNumber; i++)
		{
			int r = masterNumber%10;
			masterNumber = masterNumber/10;
			reverseIt = reverseIt * 10 + r;
			i=0;
		}
 
	Finalize(masterNumber, reverseIt);
	}

masterNumber is being passed in from a module above, and of course reverse it is being declared here in this module. At the end Finalize is being called and both variables are being passed into this method. The problem I am having is masterNumber is being overwritten in this module, so when it get's passed it is showing a null value. What do I need to change in order that masterNumber keeps it's original value declared in it's module?

**aussiemcgr** · May 7th, 2012, 03:39 PM

Well, first off, I'm not sure why masterNumber would be null. I don't think ints can even be null...

Second, masterNumber is being changed in your for statement, by the line:

masterNumber = masterNumber/10;

The only way to keep the value that was sent to the method is by declaring another local variable, setting its value to masterNumber, and then performing your operations on the new local variable. Since int is just a primitive, saying:

int var = masterNumber;

will set var to the current value of masterNumber, opposed to its location in memory, meaning you can make changes to var or masterNumber without effecting the other variable.

**jo15765** · May 7th, 2012, 07:03 PM

Originally Posted by aussiemcgr

int var = masterNumber;

.

Such a simple solution! I don't know why I didn't think of that! One more question...I think I have my if...else statement set up improperly. What it is supposed to do is if masterNumber equals reverseIt then display they match. If masterNumber does not equal reverseIt display No Match. But it is displaing they match regardless of the case.

		if(masterNumber != reverseIt)
 
			JOptionPane.showMessageDialog(null, "They match");
 
			else
 
				JOptionPane.showMessageDialog(null, "No match");

Does that look set up properly to you?

**Norm** · May 7th, 2012, 07:56 PM

print out the values of both variables before the if test so you can see their values and know why the if statement is doing what it is doing.

**jo15765** · May 7th, 2012, 08:00 PM

When I print the value of the variables, they display properly (as they should). That's why I was curious if I wrote my If statement wrong.

**Norm** · May 7th, 2012, 08:03 PM

If you print the values of the variables, then you should not be surprised by what the if statement does.
Can you explain? Post the values that are printed and what message was displayed.

**jo15765** · May 7th, 2012, 08:09 PM

I was comparing the wrong 2 variables. Beginner's error. Thank you for the help! (As well as the future tip of printing the variables when results are not looking like I think they should)

**Norm** · May 7th, 2012, 08:12 PM

I use printlns a lot when I'm wondering what the computer is seeing.

**jo15765** · May 7th, 2012, 08:13 PM

How would I use that?

**Norm** · May 7th, 2012, 08:15 PM

A sample:

   System.out.println("M @ " + getPos(Mouse) + " cheese @ " + getPos(Cheese));
 
     System.out.println("  after set row=" + oldRow + ", col=" + oldCol + " sqr=" + maze[oldRow][oldCol]);

**jo15765** · May 7th, 2012, 08:17 PM

Cool

I'll make a note of this, and use it in future coding projects!

**TheNextBillGates** · May 7th, 2012, 08:18 PM

Originally Posted by jo15765

if(masterNumber != reverseIt) JOptionPane.showMessageDialog(null, "They match");
else JOptionPane.showMessageDialog(null, "No match");

you wrote:

if masterNumber is not equal to reverseIt then display "They Match"
else (if masterNumber is equal to reverseIt) display "No Match"

try:

if(masterNubmer.equals(reverseIt) JOptionPane.showMessageDialog(null, "They Match!");
else JOptionPane.showMessageDialog(null, "No Match.");

**Norm** · May 7th, 2012, 08:22 PM

if(masterNubmer.equals(reverseIt)

@TheNextBillGates
Do you know if the variables are object references or primitives?

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