NbitsStrings.java

import java.util.*;
public class NbitsStrings {
	int[] arrA;

	public NbitsStrings(int n) {
		arrA = new int[n];
	}

	public void nBits(int n) {
		if (n <= 0) {
			System.out.println(Arrays.toString(arrA));
		} else {
			arrA[n - 1] = 0;
			nBits(n - 1);
			arrA[n - 1] = 1;
			nBits(n - 1);
		}
	}

	public static void main(String[] args) throws java.lang.Exception {
		int n = 3;
		NbitsStrings i = new NbitsStrings(n);
		i.nBits(n);
	}
}