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[java] Probabilty Problem

Started by Nomad010 Nov 12, 2004 at 11:38 AM 9 replies 900+ views

Original Post

Nov 12, 2004 at 11:38 AM

While doing work on a game, I came across a problem where I needed to a boolean that was true only 1 millionth of the time. Does anyone know of any Java code or classes available to allow me to do that?

nagromo

Nov 12, 2004 at 11:56 AM

Quote:
Original post by Nomad010
While doing work on a game, I came across a problem where I needed to a boolean that was true only 1 millionth of the time.

Does anyone know of any Java code or classes available to allow me to do that?

"I needed to a boolean"

What do you mean by this? It might have just been a typo, but please fix it so we know what you mean and can help.

Rebooted

Nov 12, 2004 at 12:15 PM

Call Java's random function, and if the return value is 1 million, set your bool to true. Otherwise, set it to false.

Nomad010

Nov 12, 2004 at 1:13 PM

Java's Math.random function only produces a random number from 0.000 to 1.000. There are only 1001 possibilities.

Thex0

Nov 12, 2004 at 1:24 PM

That's a floating point number, so if((int)(Math.random()*1000000.0) == 1000000)

tombr

Nov 12, 2004 at 1:26 PM

Quote:
Original post by Nomad010
Java's Math.random function only produces a random number from 0.000 to 1.000. There are only 1001 possibilities.

Why do you think that. It says nothing about this in the javadoc. I don't know how many bits of precision you get, but it is defenitly more than you need.

pinacolada

Nov 12, 2004 at 1:38 PM

Don't use Math.random, use java.util.Random, and call nextInt(). The code looks like this:

//create the random, note how we seed itRandom r = new Random(System.currentTimeMillis());// ....boolean bOneInAMillion = (r.nextInt() % 1000000) == 0;

ps. floating point numbers do indeed have way more than 1001 possible values

Nomad010

Nov 12, 2004 at 2:02 PM

Oops. I was confusing the Math.random() function for another class. *cough*.

Ratings++ for tombr and Thex0.

Nomad010

Nov 13, 2004 at 1:55 AM

Yeah. We all have 1000 ratings so it doesn't really do anything.

Thygrrr

Nov 13, 2004 at 3:05 AM

Are any of these two available in MIDP 1.0/2.0 ?

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