// CIS 3023 - Interfaces II problem #2, 3

abstract class Arithmetic {
	protected double result;
	protected String symbol = "";
	
	public Arithmetic(double r, String s) {
		result = r;
		symbol = s;
	}
	
	public abstract double evaluate();
}

// Addition
class Addition extends Arithmetic implements Comparable {
	private double leftOperand, rightOperand;
	
	public Addition(double r, double lo, double ro) {
		super(r, "+");
		leftOperand = lo;
		rightOperand = ro;
	}
	
	// evaluate
	public double evaluate() {
		return leftOperand + rightOperand;
	}
	
	// compareTo
	public int compareTo(Object obj) {
		Addition add = (Addition)obj;
		
		double ev1 = evaluate();
		double ev2 = add.evaluate();
		
		if (ev1 > ev2) 
			return 1;
		else if (ev1 < ev2)
			return -1;
		else
			return 0;
		
	}
}