public class RatTester extends lib.Tester {
    public static void main(String argv[]) {
   RatMetaIF maker1 = new RatMeta1(new RatRepMeta1());
   RatMetaIF maker2 = new RatMeta1(new RatRepMeta2());
        try {
            System.out.println("1/2 + 3/4 = "
              + maker1.make(1,2).add(maker1.make(3,4))
                               );
            System.out.println("1/2 + 3/4 = "
              + maker2.make(1,2).add(maker2.make(3,4))
                               );
        } catch (ZeroDenominatorException zde) {
            System.err.println("Caught ZeroDenominatorException" + zde);
        }
    }
}