// © Copyright 1999, Joseph Bergin.  All rights reserved. 

package gates;

public class Circuit
{	public boolean [] output()
	{	if(outputGates.length < outputs) return null;
		boolean [] result = new boolean[outputs];
		for(int i = 0; i < outputs; ++i)
			if( outputGates[i] != null)
				result[i] = outputGates[i].output();
			else
				result[i] = false;
		return result;
	}
	
	public Gate output(int n)
	{	if(n >= outputGates.length) return null;
		return outputGates[n];
	}
	
	public Circuit(int outputs)
	{	if(outputs < 1) outputs = 1;
		this.outputs = outputs;
		outputGates = new Gate[outputs];
	}
	
	public void connectOutput(Gate g)
	{	if(nextFreeOutput < outputs)
			outputGates[nextFreeOutput++] = g;
	}
	
	private int outputs = 1;
	private Gate [] outputGates = null;
	private int nextFreeOutput = 0;
}

class Adder extends Circuit
{	public Adder(Gate in1, Gate in2)
	{	super(2);
		NotGate flipLeft = new NotGate(in1);
		NotGate flipRight = new NotGate(in2);
		AndGate left = new AndGate(in1, flipRight);
		AndGate right = new AndGate(in2, flipLeft);
		OrGate combine = new OrGate(left, right);
		AndGate carry = new AndGate(in1, in2);
		
		connectOutput(combine);	
		connectOutput(carry);
	}
}