// Solution to CIS3023 Interfaces 1
// Problem #1, and 5

public class RationalNumber {
	private int numerator, denominator; 
	
	public RationalNumber() {
		this.numerator = 2;
		this.denominator = 1;
	}
	
	public void setDenominator(int d) {
		this.denominator = d;
	}
	
	public void setNumerator(int d) {
		this.numerator = d;
	}
	
	public int getN() {
		return numerator;
	}
	
	public int getD() {
		return denominator;
	}
	
	
	public RationalNumber(int numerator, int denominator) {
		this.numerator = numerator;
		this.denominator = denominator;
	}
	
	public RationalNumber addition(RationalNumber r2) {
		RationalNumber r = new RationalNumber();
		r.setDenominator(getD() * r.getD());
		r.setNumerator(getN() * r.getD() + r.getN() * getD());
		
		return r;
	}
	
	public RationalNumber subtraction(RationalNumber r2) {
		RationalNumber r = new RationalNumber();
		r.setDenominator(getD() * r.getD());
		r.setNumerator(getN() * r.getD() - r.getN() * getD());
		
		return r;
	}
	
	public RationalNumber multiplication(RationalNumber r2) {
		RationalNumber r = new RationalNumber();
		r.setDenominator(getD() * r.getD());
		r.setNumerator(getN() * r.getN());
		
		return r;
	}
	
	// compareTo method
	public int compareTo(Object obj) {
		RationalNumber rn = null;
		
		if (obj instanceof RationalNumber) 
			rn = (RationalNumber) obj;
		else {
			// generate exception
		}
		
		// equalize the denominators
		int n1 = getN() * rn.getD();
		int n2 = rn.getN() * getD();
		
		if (n1 > n2)
			return 1;
		else if (n1 == n2)
			return 0;
		else
			return -1;
	}
}