// Hunter Schafer, CSE 143
// Simple program that demonstrates some recursive solutions to problems
public class Recursion2 {

    public static void main(String[] args) {
        int[] array = {1, 2, 3};
        System.out.println("sum of array: " + sum(array));

    }

    // returns the sum of all the elements in the array.
    // 0 if the array is empty.
    public static int sum(int[] array) {
        return sum(array, 0);
    }

    // returns the sum of all the elements in the array starting
    // at given index. Returns 0 if index is past the end of the array.
    private static int sum(int[] array, int index) {
        if (array.length >= index) {
            return 0;
        } else {
            // array[0] + sum (array starting at index 1)
            //            array[1] + sum (array starting at index 2) == 3
            //                       array[2] + sum(array starting at index 3)
            return array[index] + sum(array, index + 1);
        }
    }
}