CODEWITHSUNDEEP
javaarrays
Éanan Halferty
Éanan Halferty

Reputation: 41

Roll dice and count arrays beginner

I want to make a simple program that rolls a dice 1000 times and counts the amount of times each number 1-6 appears. It works fine but there is an error at the end.Why is it happening?

public class diceRollerCounter {
    public static void main(String[] args) {
        int dice [] = new int[7]; 
        for(int x = 0 ; x <1000; x++ ) {
            ++dice [(int)(Math.random()*6+1)];
        }
        System.out.println("Number       Frequency" );  
        for(int index = 0; 1 < dice.length ; index++) {
            System.out.println(index + "            " + dice[index]);
        }
    }
}

OUTPUT:

Number       Frequency
0            0
1            170
2            143
3            188
4            165
5            173
6            161
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 7
    at diceRollerCounter.main(diceRollerCounter.java:20)

Upvotes: 0

Views: 4145

Answers (1)

rgettman
rgettman

Reputation: 178253

Your for loop condition tests if 1 is less than dice.length, and it's always true. But you keep incrementing index until it's off the end of the array.

Instead test if index is less than dice.length.

Incidentally, you may want to initialize index to 1, so that you skip the output of the number 0 appearing with a frequency of 0.

Upvotes: 3

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