public class SubSet {

  public void findSubSet(int[] a, Integer[] subSet, int i) {
		if (i == a.length) {
			printResult(subSet);
		}
		else {
			subSet[i] = (Integer) null;
			subSet(a, subSet, i + 1);
			subSet[i] = a[i];
			subSet(a, subSet, i + 1);
		}
	}

	public void printResult(Integer[] subSet) {
		for (int i = 0; i < subSet.length; i++) {
			if (subSet[i] != null)
				System.out.print(subSet[i] + " ");
		}
		System.out.println();
	}

        public static void main(String[] args) {
		int[] a = { 4, 1, -1, 6, 2, -2, 3, -3, -4, -6 };
		new SubSet().findSubSet(a, new Integer[a.length], 0);
	}

}