This program demonstrates a triangular array. : Array SubArray « Collections Data Structure « Java

1. Java
2. Collections Data Structure
3. Array SubArray

This program demonstrates a triangular array.

    

/*
 This program is a part of the companion code for Core Java 8th ed.
 (http://horstmann.com/corejava)

 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

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

    // allocate triangular array
    int[][] odds = new int[NMAX + 1][];
    for (int n = 0; n <= NMAX; 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-1)*(n-2)*...*(n-k+1)/(1*2*3*...*k)
         */
        int lotteryOdds = 1;
        for (int i = 1; i <= k; i++)
          lotteryOdds = lotteryOdds * (n - i + 1) / i;

        odds[n][k] = lotteryOdds;
      }

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

   
    
    
    
  

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