MonteCarlo

package com.company;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ThreadLocalRandom;

public class MonteCarlo {

    public static void main(String[] args) {
        List<Integer> numberOfSamplesList = convertParametersForNumberOfSamplesList(args);
        for (Integer numberOfSamples : numberOfSamplesList) {
            int numberOfPointsInCircle = computeApproximation(numberOfSamples);
            printResult(numberOfSamples, numberOfPointsInCircle);
        }
    }

    private static int computeApproximation(Integer numberOfSamples) {
        int numberOfPointsInCircle = 0;
        for (int i = 0; i < numberOfSamples; i++) {
            double x = ThreadLocalRandom.current().nextDouble(0, 1.0);
            double y = ThreadLocalRandom.current().nextDouble(0, 1.0);
            if (getDistanceFromPoint00(x, y) <= 1) {
                numberOfPointsInCircle++;
            }
        }
        return numberOfPointsInCircle;
    }

    private static double getDistanceFromPoint00(double x, double y) {
        return Math.sqrt(x * x + y * y);
    }

    private static void printResult(Integer numberOfSamples, int numberOfPointsInCircle) {
        double pi = 4 * (numberOfPointsInCircle / (double) numberOfSamples);
        System.out.println("----------------------");
        System.out.println("Liczba prob: " + numberOfSamples);
        System.out.println("Przyblizenie PI:  " + String.format("%21.20f",pi));
        double relativeError = Math.abs((Math.PI - pi) / Math.PI);
        double absoluteError = Math.abs(Math.PI - pi);
        System.out.println("Blad wzgledny:    " + String.format("%21.20f", relativeError));
        System.out.println("Blad bezwzgledny: " + String.format("%21.20f", absoluteError));
        System.out.println("----------------------");
    }

    private static List<Integer> convertParametersForNumberOfSamplesList(String[] args) {
        List<Integer> numberOfSamplesList = new ArrayList<>();
        try {
            for (String arg : args) {
                int number = Integer.parseInt(arg);
                if (number < 1) {
                    throw new NumberFormatException();
                }
                numberOfSamplesList.add(number);
            }
            if (numberOfSamplesList.isEmpty()) {
                throw new IllegalArgumentException();
            }
        } catch (NumberFormatException e) {
            System.out.println("Zly format liczby(powinna byc to liczba naturalna wieksza od zera");
        } catch (IllegalArgumentException e) {
            System.out.println("Brak parametrow uruchomienia");
        }
        return numberOfSamplesList;
    }
}