static arrays are not the same [java]

Question

I'm trying to create a Java program that generates an amount of seats taken in an airplane. So far, I have been able to do this, but my problem is every time I run the client the numbers generated are different. I need them to be the same every time...

I'm not sure what I'm doing wrong, can anybody help me?

import java.util.Random;
import java.util.Arrays;

public class Airplane {
    public static Random randomNumbers = new Random();
    public static int[] oSeatLeft = new int[10];
    public static int[] mSeatLeft = new int[10];
    public static int[] wSeatLeft = new int[10];
    public static int oSeat = 0;
    public static int mSeat = 0;
    public static int wSeat = 0;
    public static final int sCheck = 0;

    public void genWSeats() {

        int randSeatFill = 0;
        if (wSeat == 0) {
            for (int counter = 0; counter < wSeatLeft.length; counter++) {
                randSeatFill = randomNumbers.nextInt(2);
                if (randSeatFill == 1) {
                    wSeatLeft[counter] = 1;
                }
            }
            if (wSeat == 0) {
                wSeat++;
            }
        }
    }

    public int[] getWSeats() {
        System.out.println(java.util.Arrays.toString(wSeatLeft));
        return wSeatLeft;
    }
}

The purpose of static int wSeat is supposed to be a checker. If wSeat is greater than zero, then it should not randomly generate numbers for the array. Not sure exactly what is going wrong here....

I'm creating random data and its coming out randomly. What sort of magic is this? — John3136
– John3136, Commented Apr 24, 2013 at 4:56

MrSmith42 · Accepted Answer · 2013-04-24 04:54:59Z

2

Use the Random constructor with seed

public static Random randomNumbers = new Random(42);

This way always the same sequence of random numbers is generated. 42 is only an example, you can use any value you want.

answered Apr 24, 2013 at 4:54

MrSmith42

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3 Comments

Brian Murphy Over a year ago

okay great, seems to work so far. I just deleted the checker if statement, and the answers stay the same.... I assume this is okay...

Brian Murphy Over a year ago

Thanks! That helps a wicked lot! So my problem now is.... when I create multiple objects that are an extension of this class, the random numbers in each class are still the same.... is there a way to only initialize one variable, but have it generate different numbers for each class?

MrSmith42 Over a year ago

@Brian Murphy: I think this could be a little tricky. Each class would need its own static Random-instance.

Makoto · Accepted Answer · 2013-04-24 04:55:22Z

1

Pass a seed on initialization with Random(long seed). This will guarantee that the sequence of numbers generated is always the same (since it's a pseudo-random number generator).

answered Apr 24, 2013 at 4:55

Makoto

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Comments

muneebShabbir · Accepted Answer · 2013-04-24 04:57:36Z

1

Pass Seed in constructor of Random it will generate the same number every time

answered Apr 24, 2013 at 4:57

muneebShabbir

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