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public static void main(String[] args) {
	int[] a = { 0, 1, 0, 0, 0, 0, 1 };
	int[] b = { 0, 1, 1, 1, 0, 1, 1 };
	int[] c = new int[a.length];
	int carry_in = 0;
	for (int i = a.length - 1; i >= 0; i--) {
		int carry_out = 0;
		if (a[i] == 0 && b[i] == 0 && carry_in == 0) { c[i] = 0; carry_out = 0; }
		if (a[i] == 0 && b[i] == 0 && carry_in == 1) { c[i] = 1; carry_out = 0; }
		if (a[i] == 0 && b[i] == 1 && carry_in == 0) { c[i] = 1; carry_out = 0; }
		if (a[i] == 0 && b[i] == 1 && carry_in == 1) { c[i] = 0; carry_out = 1; }
		if (a[i] == 1 && b[i] == 0 && carry_in == 0) { c[i] = 1; carry_out = 0; }
		if (a[i] == 1 && b[i] == 0 && carry_in == 1) { c[i] = 0; carry_out = 1; }
		if (a[i] == 1 && b[i] == 1 && carry_in == 0) { c[i] = 0; carry_out = 1; }
		if (a[i] == 1 && b[i] == 1 && carry_in == 1) { c[i] = 1; carry_out = 1; }
		carry_in = carry_out;
	}
	System.out.println(Arrays.toString(c));
}