// INHERIT0_DETAILED
// more about assigning objects of different types
// discussed more during polymorphism

/* Purpose:
 * Imagine that $double$ is `wide' and $int$ is `thin'.
 * Based on numbers and type, an integer is (or, can be) a double.
 * So, doubles resemble superclasses of integers.
 * Can also say, doubles as `wider' than integers.
 */

class wide {}              // `double' (class A)
class thin extends wide {} // `int'    (class B)

public class inherit0_detailed {
   public static void main(String[] args) {

/***************************************************************************************************/
/* Assignment       Types        Type   Var  Value              Output                             */
/***************************************************************************************************/
/* wide gets wide:  primitive */ double y1 = 1.2;               System.out.println(y1);
/* wide gets wide:  object    */ wide   x1 = new wide();        System.out.println(x1.getClass());
/* wide gets thin:  primitive */ double y2 = 1;                 System.out.println(y2);
/* wide gets thin:  object    */ wide   x2 = new thin();        System.out.println(x2.getClass());
/* wide gets thin:  primitive */ double y3 = (double) 1;        System.out.println(y3);
/* wide gets thin:  object    */ wide   x3 = (wide) new thin(); System.out.println(x3.getClass());
/* thin gets thin:  primitive */ int    y4 = 1;                 System.out.println(y4);
/* thin gets thin:  object    */ thin   x4 = new thin();        System.out.println(x4.getClass());
/* thin gets wide:  primitive */ int    y5 = (int) 7.7;         System.out.println(y5);
/* thin gets wide:  object    */ thin   x5 = (thin) new wide(); System.out.println(x5.getClass());

// Note: the x3 and y3 assignments are redundant versions of x2 and y2, respectively.

// Another trick to remembering:
// If Y is an X, then $X var = new Y()$ is OK.
// Also, Y is a Y, so $Y var = new Y()$ is OK.

   } 
}

/* output:
   1.2
   class wide
   1.0
   class thin
   1.0
   class thin
   1
   class thin
   7
   Exception in thread "main" java.lang.ClassCastException: wide
        at itest.main(itest.java, Compiled Code)
   ^^^ 
    Why an Exception? Java has trouble reversing is-a relationships
    because the superclass might not contain vars/meths written in the subclass.
*/