public int compareTo(Rational other) {
if (num.equals(other.num) && den.equals(other.den)) return 0;
// see if it is a num only compare...
if (den.equals(other.den)) return (greater(other.num, this.num)) ? -1 : 1;
// check signs...
if ((zero(num) || negative(num)) && positive(other.num)) return -1;
else if (positive(num) && (zero(other.num) || negative(other.num))) return 1;
BigInteger c1 = new BigInteger(other.num.toString());
BigInteger c2 = new BigInteger(other.den.toString());
Rational c = new Rational(c1, c2);
c = c.negate();
c.addEq(this);
return (c.isZero() ? 0 : (negative(c.num) ? -1 : 1));
}
public Rational subtract(Rational b) {
if (zero(b.num)) return this;
Rational c = b.negate();
if (!zero(num)) c.addEq(this);
return c;
}