ThreeFourFiveLotto.java

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Random;
import java.util.Scanner;

public class ThreeFourFiveLotto {

    /**
    *   Program: ThreeFourFiveLotto.java
    *   Purpose: Lotto program uses ArrayList, chooses 3, 4 or 5 numbers
    *   Creator: Chris Clarke
    *   Created: 27.08.2015
    */

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        ArrayList<Integer> arl = new ArrayList<Integer>();
        int selection;
        int numBalls;

        System.out.print("How many balls to draw (3, 4 or 5)? ");
        do {
            numBalls = in.nextInt();
            if (numBalls<3 || numBalls>5) System.out.print("Error! Must be 3, 4 or 5: ");
        } while (numBalls<3 || numBalls>5);

        int[] chosen = new int[numBalls];

        // initialise the array list
        for (int index=0; index<HIGHEST_NUMBER; index++) {
            arl.add(new Integer(index+1));
        }

        // create random object
        Random ran = new Random();

        for (int i=0; i<numBalls; i++) {
            selection = ran.nextInt(arl.size());
            chosen[i] = arl.get(selection);
            // remove from ArrayList so not chosen again
            arl.remove(selection);
        }

        // sort chosen numbers into ascending order
        Arrays.sort(chosen);

        System.out.println("Here are your random lotto numbers: ");

        // enhanced for loop
        for (int i: chosen) {
            System.out.print(i + " ");
        }
    }

    private static final int HIGHEST_NUMBER = 49; // change this if necessary
}