objectarray.java

Java程序设计技巧与开发实例附书源代码。

public class ObjectArray
{
   public static void display(Object obj)
   {
      if (obj instanceof Rectangle)
      {
         System.out.println( ( (Rectangle) obj).toString());
      }
      else if (obj instanceof Circle)
      {
         System.out.println( ( (Circle) obj).toString());
      }
      else if (obj instanceof Double)
      {
         System.out.println( ( (Double) obj).toString());
      }
      else if (obj instanceof Integer)
      {
         System.out.println( ( (Integer) obj).toString());
      }
   }

   public static void main(String args[])
   {
      Object objects[] = new Object[4];
      objects[0] = new Rectangle(3, 4);
      objects[1] = new Circle(5);
      objects[2] = new Double(1.0);
      objects[3] = new Integer(2);
      for (int i = 0; i < objects.length; i++)
      {
         display(objects[i]);
      }
   }
}