How do I generate a random number between 1 and 6 in java?

[gkeown]

Trying to build a program that rolls random die numbers.
I'm trying to use Math.random to generate random numbers in this for loop. I just need to get the code so it generates a number between 1 and 6 each time - here's the code.

import javax.swing.JOptionPane;

public class Array2 {

public static void main(String[] args) {

int frequency[] = new int[7];
frequency[0] = 1;
frequency[1] = 2;
frequency[2] = 3;
frequency[3] = 4;
frequency[4] = 5;
frequency[5] = 6;

int count1 = 0, count2 = 0, count3 = 0, count4 = 0, count5 = 0, count6 = 0;

for(int i=0; i <= 9999; i++)
{
frequency[i] = Math.random()*6;

if(frequency[i] == 1)
count1++;

if(frequency[i] == frequency[1])
count2++;

if(frequency[i] == frequency[2])
count3++;

if(frequency[i] == frequency[3])
count4++;

if(frequency[i] == frequency[4])
count5++;

if(frequency[i] == frequency[5])
count6++;
}

System.out.println(count1);

}
}
Nevermind, I was making a massive cock up. Fixed now.

import javax.swing.JOptionPane;

public class Array2 {

public static void main(String[] args) {

int frequency[] = new int[10000];

int count1 = 0, count2 = 0, count3 = 0, count4 = 0, count5 = 0, count6 = 0;

for(int i=0; i <= 9999; i++)
{
frequency[i] = (int)(Math.random()*6) + 1;

if(frequency[i] == 1)
count1++;

if(frequency[i] == 2)
count2++;

if(frequency[i] == 3)
count3++;

if(frequency[i] == 4)
count4++;

if(frequency[i] == 5)
count5++;

if(frequency[i] == 6)
count6++;
}

System.out.println(count1);
System.out.println(count2);
System.out.println(count3);
System.out.println(count4);
System.out.println(count5);
System.out.println(count6);

}
}
I only had JOptionPane imported as a pre-requisite. Incase the next thing I work on needs it!

Cheers fellas.

[pete_monkey_hanger]

just look for random number gen class and add it to you code

[wiseoldd]

JOptionPane is for text input, you dont seem to have any show input dialog methods so i wouldnt think its necessary. Math.random((double))*1000 generates integers so try using that the rest of the details i am a little rusty on.

[deonejuan]

import java.util.Hashtable;
import java.util.Random;

public class DieFreqs {

static private Hashtable<Integer, Integer> hashT =
new Hashtable<Integer, Integer>();

public static void main(String[] args) {
for (int i = 1; i <= 6; i++) {
hashT.put(new Integer(i), 0);
}

for (int i = 0; i < 10000; i++) {
Integer randomNum = getRand();
int curValue = hashT.get(randomNum);
curValue++;
hashT.put(randomNum, curValue);

}
System.out.println("Frequencies: "+hashT.toString());
}

private static Integer getRand() {
Random r = new Random();

return new Integer( r.nextInt(6) +1);

}

}
//>===================
if you don't want to use modern API, maybe this will give you ideas.

java.util.Random is more convenient than Math.random().
the die is r.nextInt(6) + 1; for 1 to 6 inclusive
Hasthtable is the same as an Array, except we use a key instead of an Index. Hashtable<name, value>