// Fig. 10.1: HierarchyRelationshipTest1.java
// Assigning superclass and subclass references to superclass- and
// subclass-type variables.
import javax.swing.JOptionPane;

public class HierarchyRelationshipTest1 {

  public static void main( String[] args )
  {
    // assign superclass reference to superclass-type variable
    Point3 point = new Point3( 30, 50 );

    // assign subclass reference to subclass-type variable
    Circle4 circle = new Circle4( 120, 89, 2.7 );

    // invoke toString on superclass object using superclass variable
    String output = "Call Point3's toString with superclass" +
                    " reference to superclass object: \n" + point.toString();

    // invoke toString on subclass object using subclass variable
    output += "\n\nCall Circle4's toString with subclass" +
              " reference to subclass object: \n" + circle.toString();

    // invoke toString on subclass object using superclass variable
    Point3 pointRef = circle;
    output += "\n\nCall Circle4's toString with superclass" +
              " reference to subclass object: \n" + pointRef.toString();

    JOptionPane.showMessageDialog( null, output );  // display output

    System.exit( 0 );

  } // end main

} // end class HierarchyRelationshipTest1