class ArrayFinder {
	public static void main(String [] args) {
		int [] arr = {10, 20, 30, 40};

		System.out.println(find(arr, 20));
		System.out.println(find(arr, 35));
	}

	static int find(int [] array, int val) {return find(array, 0, array.length-1, val);}

	static int find(int [] array, int first, int last, int val) {
		if (first > last) return -1;

		if (array[first] == val) return first;
		return find(array, first+1, last, val);
	}
}