BigInteger Adam/Phil

/*
 * Name:Philip Crafts/Adam Tiago
 * Date:10/27/2017
 * Course Number:CSC-220
 * Course Name:Data Structure
 * Problem Number: HW5
 * Email:[email protected]
 * Simple program that shows the number of possible combinations of individual items
 * that can be selected from a single group
 */

import java.math.BigInteger;
import java.util.Scanner;

public class BigIntegerCombination {


    //**********************************************

    private static void process(Scanner sc, String args[]) {
        int n;
        int k;

        System.out.println("Enter N: ");
        n = sc.nextInt();
        System.out.println("Enter K: ");
        k = sc.nextInt();
        sc.nextLine();


        System.out.println("C(n,k) is ");
        System.out.println(getNumberOfCombinations(n,k).toString()+"\n<End Output>\n");
    }

    private static BigInteger getNumberOfCombinations(int n, int k) {
        BigInteger output;

        output = (factorial(n).divide( (factorial(k).multiply(factorial((n-k)))) ));

        return output;
    }

    private static BigInteger factorial(int i) {
        BigInteger factorial = new BigInteger("1");
        BigInteger hold = new BigInteger("1");

        for(int j = 2 ; j <= i ; j++)
        {
            hold = new BigInteger(Integer.toString(j));
            factorial = hold.multiply(factorial);
        }

        return factorial;
    }

    //**********************************************

    private static boolean doThisAgain(Scanner sc, String prompt) {
        System.out.print(prompt);
        String doOver = sc.nextLine();
        return doOver.equalsIgnoreCase("Y");
    }

    //**********************************************

    public static void main(String args[]) {
        final String TITLE = "CSC111 Project Template";
        final String CONTINUE_PROMPT = "Do this again? [y/N] ";

        System.out.println("Welcome to " + TITLE);
        Scanner sc = new Scanner(System.in);
        do {
            process(sc, args);
        } while (doThisAgain(sc, CONTINUE_PROMPT));
        sc.close();
        System.out.println("Thank you for using " + TITLE);
    }

}