LotteryArray.java

package Lottery;

/**
 * This program demonstrates a triangular array.
 *
 * @author Cay Horstmann
 * @version 1.20 2004-02-10
 */
public class LotteryArray {
    public static void main(String[] args) {
        final int N_MAX = 10;

        // allocate triangular array
        int[][] odds = new int[N_MAX + 1][];
        for (int n = 0; n <= N_MAX; n++)
            odds[n] = new int[n + 1];

        // fill triangular array
        for (int n = 0; n < odds.length; n++) {
            for (int k = 0; k < odds[n].length; k++) {
                /*
                 * compute binomial coefficient n*(n-l)*(n-2)*...*(n-k+l)/(l*2*3*...*k)
                 */
                int lotteryOdds = 1;
                for (int i = 1; i <= k; i++) {
                    lotteryOdds = lotteryOdds * (n - i + 1) / i;
                }

                odds[n][k] = lotteryOdds;
            }
        }

        for (int[] row : odds) {
            for (int odd : row) {
                System.out.printf("%4d", odd);
            }
            System.out.println();
        }
    }
}