class ALU {

	public String negation (String operand) {
		StringBuilder builder = new StringBuilder(operand);
		for(int i=0;i<operand.length();i++){
			char bit = builder.charAt(i);
			bit = charOp(booleanXOR, bit, '1');
			builder.setCharAt(i, bit);
		}
		return builder.toString();
	}

}