Java random array of numbers

Question

I am trying to make an array of random numbers that range from 0-9 with the variable for this one being kickerNumbers. I get a compile error though saying incompatible types. I have tried changing the (int) to [int] like it said but I didn't think that would be right anyway and surly enough it wasn't. Is there another way to write this? I need it to act as the first four numbers of this to be 0-9 but the fifth number would need to be something smaller such as 0-4. for the 0-4 one I just made that a completely different variable. Was that a good choice? Here is the sample code for the lines that give the error.

import java.util.Scanner;
import java.util.InputMismatchException;
public class CashBallTest
{
    public static void main(String[]args)
    {
        Scanner keyboard = new Scanner(System.in);
        int kicker;
        int[] kickerNumbers = (int)(Math.random()*0+9);
        int kickerPowerball=(int)(Math.random()*0+4);

The error reads:

\CashBallTest.java:9: incompatible types
    found   : int
    required: int[]
    int[] kickerNumbers = (int)(Math.random()*0+9);

I have also tried changing (int) to (int[]) but then it said it was an inconvertible type counting as a double when it needs to be an int[] but I don't see where it gets the double type from.

Sean Connolly · Accepted Answer · 2015-01-06 19:57:58Z

7

int[] kickerNumbers = (int)(Math.random()*0+9);

You can't assign an int to an int[]

Assuming that is supposed to be more the one number, it might be something like this

int[] kickerNumbers = new int[5];
for(int i = 0; i < kickerNumbers.length; i++) {
    kickerNumbers[i] = (int)(Math.random()*0+9);
}

On an unrelated note, why are you multiplying the Math.random()*0? That seems silly to me. If you want a number 1 through 10, I would do this: Math.random()*10 + 1

edited Jan 6, 2015 at 19:57

Sean Connolly

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answered May 2, 2011 at 21:41

corsiKa

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1 Comment

MByD Over a year ago

+1 for pointing out the random() issue. (and posting before me :) )

MByD · Accepted Answer · 2011-05-02 21:43:26Z

4

This is an int array: int[] kickerNumbers but you assign it with int (not array) (int)(Math.random()*0+9);
your random will return 9. always (operator precedence).

Create an array like this: int[] kickerNumbers = int[numberOfPlayers] and assign numbers in loop, or use ArrayList with numbers from 0-9 and call shuffle

answered May 2, 2011 at 21:43

MByD

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Comments

Witold Kaczurba · Accepted Answer · 2017-03-16 14:35:12Z

4

Simply:

java.util.Random r = new java.util.Random();
int[] kickerNumbers = r.ints(0, 10).limit(5).toArray(); // 5 times 0...9

Then change last element:

kickerNumbers[4] = r.nextInt(5);

answered Mar 16, 2017 at 14:35

Witold Kaczurba

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Comments

Peter Lawrey · Accepted Answer · 2011-05-02 21:59:47Z

3

It may be work using your own random number generator so you can use nextInt and avoid some confusion.

Random r = new Random();
// four values [0, 9]
int[] kickerNumbers={r.nextInt(10), r.nextInt(10), r.nextInt(10), r.nextInt(10)};
// one value [0, 4]
int kickerPowerball = r.nextInt(5);

answered May 2, 2011 at 21:59

Peter Lawrey

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2 Comments

MByD Over a year ago

+1 for r.nextInt(). better than the games with Math.random()

Peter Lawrey Over a year ago

And faster, but that doesn't matter here. ;)

Declan Cook · Accepted Answer · 2011-05-02 22:05:50Z

You're attempting to assign an int to an array which is what is giving you the error.

what you want to do it use a loop to iterate through your array and assign random values to it, you mentioned that you wanted your numbers to be between 0-9 and 0-4 the following code will give you that result:

public static void main(String[] args) {
    int[] kickerNumbers = new int[4];
    for (int i = 0; i < kickerNumbers.length; i++) {
        kickerNumbers[i] = randomRange(0,9);
    }
    int kickerPowerball = randomRange(0,4);
}
public static int randomRange(int min, int max) {
    return (int) Math.round(((Math.random() * (max - min)) + min));
}

the code above includes a method that will return a integer between to given parameters.

Tsagana Nokhaeva · Accepted Answer · 2017-10-22 15:55:20Z

0

import java.util.Random;
public class CashBallTest {

    public static void main (String[]args){

        int[] kickerNumbers= new int[5];
        for (int i=0;i<4;i++)
            kickerNumbers[i]=randomize(9);
            kickerNumbers[4]=randomize(4);

        for (int i:kickerNumbers)
            System.out.println(i);
    }

    public static int  randomize(int k){
        Random rand=new Random();
        return rand.nextInt(k);
    }
}

Assuming you don't care for duplicates.

Sorry. I had not read answer from Peter... It is just the same.

edited Oct 22, 2017 at 15:55

Tsagana Nokhaeva

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answered May 2, 2011 at 22:08

luis acevedo

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1 Comment

Stephen P Over a year ago

You also should not get a new Random() every time.

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