/**
 * Generate an array of 10000 random numbers from 0 to 4.
 * Report the percentage of each number (0,1,2,3 and 4)
 * Use methods to do each task.
 */

import java.text.*;
import javax.swing.*;

public class RandomArray {

    /**
     * Creates an array of integers(of size 10000). Fills the array
     * with integers randomly chosen between 0 and 4. Computes and prints the number
     * of occurences of each integer as a percentage.
     */
    public void processRandomArray()
    {
        // Define an array of integers of size 10000
        int[] array = new int[10000];
        // Fill the array with random numbers between 0 and 4
        // Use the method fillRandomly
        this.fillRandomly(array);
        // Report the percentage of each number
        // Use the method report
        this.computeAndPrintReport(array);
    }

    /**
     * Fills an array with random integers between 0 and 4
     * @param a the array to fill
     */
    private void fillRandomly(int[] a)
    {
        // Fill the array with random numbers between 0 and 4
        for (int i = 0; i < a.length; i ++) {
            a[i] = (int) (Math.random() * 5);
        }
    }

    /**
     * Computes and prints the percentage of occurences of 0,1,2,3 and 4 in an array
     * @param a the array to scan.
     */
    private void computeAndPrintReport(int[] a)
    {
        // one way
        int n0 = 0, n1 = 0, n2 = 0, n3 = 0, n4 = 0;
        for (int i = 0; i < a.length; i ++) {
            switch (a[i]) {
                case 0: n0 ++; break;
                case 1: n1 ++; break;
                case 2: n2 ++; break;
                case 3: n3 ++; break;
                case 4: n4 ++; break;
            }
        }
        String s = "";
        s += "Number of 0's = " + (100.0 * n0 / a.length) + "%\n";
        s += "Number of 1's = " + (100.0 * n1 / a.length) + "%\n";
        s += "Number of 2's = " + (100.0 * n2 / a.length) + "%\n";
        s += "Number of 3's = " + (100.0 * n3 / a.length) + "%\n";
        s += "Number of 4's = " + (100.0 * n4 / a.length) + "%\n";
        JOptionPane.showMessageDialog(null, s, "Results", 
        JOptionPane.INFORMATION_MESSAGE);
        
        // other way
        int[] count = new int[5];
        for (int i = 0; i < a.length; i ++) {
            count[a[i]] ++;
        }
        StringBuffer sb = new StringBuffer();
        NumberFormat nf = NumberFormat.getPercentInstance();
        nf.setMaximumFractionDigits(2);
        nf.setMinimumFractionDigits(2);
        for (int i = 0; i < count.length; i ++) {
            sb.append("Number of " + i + "'s = " + 
            nf.format((double) count[i] / a.length) + "\n");
        }
        // Print s as well to compare with sb
        JOptionPane.showMessageDialog(null, s + "\n\n" + sb.toString(), "Results", 
        JOptionPane.INFORMATION_MESSAGE);
    }










}