/**
 * Verweise.java
 * 
 * Ein Programm, das die Funktionsweise von Verweisen demonstriert.
 */

class Verweise {

  public static void main(String[] args) {

    // Definitionen
    Point p1, p2;

    // Initialisieren

    p1 = null;
    p2 = new Point();

    System.out.println();
    System.out.println("Die Werte der Referenzvariablen sind:");
    System.out.println();
    System.out.println("   p1 = " + p1);
    System.out.println("   p2 = " + p2);
    System.out.println();

    // Das kann zur Zeit nicht gut gehen:
    // System.out.println(" p1 = (" + p1.x + "," + p1.y + ")");

    // Erzeugen von p1 und Verschieben von p2

    p1 = new Point();
    p2.moveTo(2, 3);

    System.out.println();
    System.out.println("Klassen sind Referenz-Datentypen:");
    System.out.println();
    System.out.println("   p1 = " + p1);
    System.out.println("   p2 = " + p2);
    System.out.println();

    System.out.println("   p1 = (" + p1.x + "," + p1.y + ")");
    System.out.println("   p2 = (" + p2.x + "," + p2.y + ")");
    System.out.println();

    System.out.println("Jetzt wird p2 = p1 gesetzt.");
    System.out.println();

    p2 = p1;

    System.out.println("   p1 = " + p1);
    System.out.println("   p2 = " + p2);
    System.out.println();

    System.out.println("Nach dem Verschieben von p1 nach (4,5):");

    p1.moveTo(4, 5);

    System.out.println();
    System.out.println("   p1 = (" + p1.x + "," + p1.y + ")");
    System.out.println("   p2 = (" + p2.x + "," + p2.y + ")");
    System.out.println();
  }
}

// Verweise