Problem 20

/**
 *
 * @author Mat
 */
package Fact100;

import java.math.BigInteger;

public class Fact100Add {

    public static void main(String[] args) {
        // set as one as the first factorial is 1*
        BigInteger number1 = new BigInteger("1");

        //loop through multiplying n= n*(n+1)
        for(BigInteger i = new BigInteger("2");
                i.compareTo(BigInteger.valueOf(100)) <= 0; i = i.add(BigInteger.ONE)){
            number1 = number1.multiply(i);
        }

        System.out.println("!100 factorial is\n" + number1.toString());

        //creates a new string object which is number1
        String s = number1.toString();
        int totalnum = 0;


        //loop through each number of the array turn it into a int and add to total
        for(int i = 0;i < s.length();i++){
            totalnum+=Integer.parseInt(s.substring(i, i+1));
        }

        System.out.println("Added together is " + totalnum);
    }
}
/* Output
 * !100 factorial is
 * 93326215443944152681699238856266700490715968264381621468592963895217599993229
 * 91560894146397615651828625369792082722375825118521091686400000000000000000000
 * 0000
 * Added together is 648
 */