Odd And Even

[freesoft_2000]

Hi everyone,

I am doing a simple program with some text in the jtextpane and the text inside the jtextpane span to about three standard A4 papers. What i want to do is to only be able print even and odd pages. I am using currently the java printable interface in which i must overide the print method which has the following declaration

public int print(Graphics pg, PageFormat pageFormat, int pageIndex)
{
}

I Know that printing even or odd pages does not involve the graphics or the pageformat objects.

The pageindex object is the one i am concerned about.

The thing is i do not know how to test as to whether the pageindex is an even or odd number (including 0 which is an odd number)

Can anyone show me any codings or explain to me in detail how to test for even or odd numbers.

Thank You

Yours Sincerely

Richard West

[Belisarius]

That's one of those things in Java I never found out if there was a good way of doing it. It's kinda odd that Integer or Math doesn't have an even/odd method. But even so, this is pretty a basic computer science/math problem, so there are probably a million different ways to do it.

I'm assuming we're working with integers here. The result of any mathematical operation that has a fraction/decimal will have the partial number chopped off, not rounded (good thing in this case). As a result, you can do something like this:

int a = 15;
int b = a \ 2; // Might want to idiot check me on the divide symbol.
if ( (b * 2) == a ){
  // It's even
}else{
  // It's odd
}

The result of this is that b will equal 7, because the .5 gets chopped off. Because 7 * 2 != 15, we know it's odd.

[inkedmn]

the easiest way would be something like:

if(pageindex % 2 == 0)
    // then it's even
else
    // then it's odd

the modulus operator (%) returns the remainder of any division operation. Here's a python example (since it's easier to read/understand)

>>> 3 % 2
1
>>> 14 % 7
0

because 14 divides evenly by 7, there's no remainder, but 3 doesn't divide evenly by 2, so there's a remainder of 1, etc.

hth

[Belisarius]

Ah yeah, I forgot about modulus. That's an even better way to do it.