RandomNumberBucketArray.java

package org.drip.zen.numbers;

public class RandomNumberBucketArray {

    public static double CalculatePercentage (int count, int total)
    {
        double percent = 100. * (double) count / (double) total;
        return percent;
    }

    public static int FindBucketIndex (double number, int totalBuckets)
    {
        int bucketIndex = 0;
        double bucketWidth = 1. / totalBuckets;

        for (int i = 0; i < totalBuckets; i = i + 1) {
            double bucketLeftEnd = i * bucketWidth;
            double bucketRightEnd = (i + 1) * bucketWidth;

            if (number > bucketLeftEnd && number <= bucketRightEnd)
                bucketIndex = i;
        }

        return bucketIndex;
    }

    public static void main (String[] args)
    {
        int numberOfBuckets = 10;

        int[] countbucket = new int[numberOfBuckets];

        int totalTrials = 10000;
        int trialNumber = 1;

        while (trialNumber <= totalTrials)
        {
            double randomNumber = Math.random();

            int randomNumberBucket = FindBucketIndex (randomNumber, numberOfBuckets);

            countbucket[randomNumberBucket] = countbucket[randomNumberBucket] + 1;

            trialNumber = trialNumber + 1;
        }

        String countString = "\t| ";

        for (int i = 0; i < numberOfBuckets; i = i + 1)
            countString = countString + countbucket[i] + " | ";

        System.out.println (countString);

        String countPercentString = "\t| ";

        for (int i = 0; i < numberOfBuckets; i = i + 1)
            countPercentString = countPercentString + CalculatePercentage (countbucket[i], totalTrials) + "% | ";

        System.out.println (countPercentString);
    }
}