/**
 * Client to test the Length class on the empty list, a one-element list, and
 * a two-element list
 * @author DXN
 */
public class TestLength {

    /**
     * Calls the Length class to calculate the length of a list and prints the
     * result.
     * @param list an AList whose length is to be computed and printed.
     */
    private void testLength(AList list) {
        System.out.println(list + " has length " + Length.CalcLen(list));
    }

    /**
     * Creates the empty list, a one-element list, a two-element list and
     * prints out their lengths.
     */
    public void run() {
        AList e0 = EmptyList.Singleton;
        testLength(e0);
        AList e1 = new NEList("one", e0);
        testLength(e1);
        AList e2 = new NEList("two", e1);
        testLength(e2);
    }

    /**
     * Main entry point to test program.
     * @param nu not used.
     */
    public static void main(String[] nu) {
        new TestLength().run();
    }
}