public static void main(String[] args) {
		
		//This program determines the even factorial of an even positive integer
		//ie: n(n-2)(n-4)....4*2
		
		int positiveInt;
		Scanner input = new Scanner(System.in);
		
		for (;;) {
			
			System.out.print("Please enter a positive even integer (0 to exit): ");
			positiveInt = input.nextInt();
			
			if (positiveInt == 0) {
				//terminal value
				break;
				
			} else if (positiveInt < 0) { //no negative values permitted
				
				System.out.println("The number entered is negative.");
				
			} else if ((positiveInt%2) != 0) { //no odd numbers permitted
				
				System.out.println("The number entered in not an even number.");
				
			} else {
				//for even positive numbers, call the method even_factorial and display the results
				System.out.println("The factorial value of " + positiveInt + " is " + even_factorial(positiveInt) + ".");
			}
		}
		
		input.close();

	}