Rolling dice project: code gives out of bounds exception below 7 and fails to save the first “Die Number”



I understand what out of bounds exception means, and how it happens, but I can’t find out why it’s happening in my code. Also, the output “Count for side 1” always states 0. This is my first post, but I think I am posting this right.

This is where I think the problem is.

System.out.println("Now rolling " + chosenRollNumber + " times. ");
            int[] count = new int[chosenRollNumber];
            for (x = 0; x < chosenRollNumber; x++) {
                dieNumber = RNG(randomNum, min, max);
                System.out.println("dieNumber " + dieNumber);
                count[dieNumber]++;

            }
            System.out.println("Done rolling all dice");    
            for(x = 0; x < numberOfSides; x++) {
                System.out.println("Count for side " + (x + 1) + " is " + count[x]);            }

            while(true) {

Answer

Method RNG(randomNum, min, max) is expected to return values in the range [min...max] (inclusive), while dieNumber as the index in count array needs to be in the range [0; numberOfSides), and the following relation exists numberOfSides == max - min + 1.

So, a correction is needed to transform dieNumber into a valid index:

System.out.println("Now rolling " + chosenRollNumber + " times. ");
int[] count = new int[numberOfSides];
for (x = 0; x < chosenRollNumber; x++) {
    dieNumber = RNG(randomNum, min, max);
    System.out.println("dieNumber " + dieNumber);
    int dieIndex = (dieNumber - min) % numberOfSides;
    count[dieIndex]++;
}


Source: stackoverflow