AddOrMultiply

import java.util.Scanner;

public class AddOrMultiply {

    public static void main(String []args) {

        enterNumber();
    }

    public static void enterNumber() {
        int userNumber;
        char userChar;
        Scanner obj = new Scanner(System.in);
        do {
            System.out.print("Enter an integer number: ");
            userNumber = obj.nextInt();

            if (userNumber == 0) {
                break;
            } else {
                System.out.print("Enter either \'a\' or \'m\' ");
                userChar = obj.next().charAt(0);

                while (userChar != 'a' && userChar != 'm') {
                    System.out.println("Invalid choice made.");
                    System.out.print("Enter either \'a\' or \'m\' ");
                    userChar = obj.next().charAt(0);
                }

                if (userChar == 'a') {
                    System.out.printf("The sum is %,d\n", getSum(userNumber));
                } else {
                    System.out.printf("The product is %,d\n", getProduct(userNumber));
                }
            }
        } while (userNumber > 0);

    }

    public static long getSum(int input) {

        if (input > 1) {
            return input + getSum(input - 1);
        } else {
            return 1;
        }
    }

    public static long getProduct(int input) {
        if (input >= 1) {
            return input * getProduct(input - 1);
        } else {
            return 1;
        }
    }

}