//References to class pointing to objects of subclass and vice versa
class App {
   public static void main(String[] args) {

      Dish d = new Dish();
      d.eat();

//    Dish ff = new MainDish(50, "light", 0);  // OK!
//    MainDish ff = new Dish(50, "light");     // Incompatible types
//    MainDish ff = d;                         // Incompatible types

      Dish dmd = new MainDish(600, "mbrizola", 15);  // OK!
//    dmd.onDiet();         // Error: dmd of type Dish
                            // => no onDiet() in scope of Dish
      dmd.eat();

//    Bla b = new Bla();
//    dmd = b;              // Incompatible types

//    MainDish md1 = dmd;   // Incompatible types: dmd of type Dish

//    MainDish md1;
//    md1 = d;              // Incompatible types

      System.out.println("////////////////");

      dmd = d;   // Now dmd refers to a Dish,
                 // no reference to "mbrizola" any longer

      dmd.eat();
      dmd.eatMore(200);

      d = dmd;   // nothing actually changes
      d.eat();

      System.out.println("////////////////");

      MainDish md1 = new MainDish(700, "patates", 3);
      MainDish md2 = new MainDish(400, "fakes", 1);

      md1 = md2;   // refs to same object

//    md2 = dmd;   // Error: incompatible types
                   // Dish cannot be converted to MainDish

      md1.eatMore(3000);
      System.out.println(md1.getCalories());
      System.out.println(md2.getCalories());
   }
}

class Bla {
   int i;
}

// abstract class Dish {
class Dish {

   int calories = 1000;
   String name = "Junk food";

   Dish() {
      System.out.println("The new dish named: " + name +
                         " contains " + calories + " calories!");
   }

   Dish(String nam) {
      name = nam;
      System.out.println("The new dish named: " + name +
                         " contains " + calories + " calories!");
   }

   Dish(int cal, String nam) {
      calories = cal;
      name = nam;
      System.out.println("The new dish named: " + name +
                         " contains " + calories + " calories!");
   }

   void eat() {
      System.out.println("Eating " + name );
   }

   void eatMore(int cal) {
      calories += cal;
      System.out.println("Eating more calories " + calories );
   }

   int getCalories() {
      return calories;
   }
}

class MainDish extends Dish {
   int cost = 6;
   MainDish(int cal, String nam, int cst) {
      super(cal, nam);
      cost = cst;
      System.out.println("The cost of the main dish is " + cost);
   }

   void eat() {
      System.out.println("Eating Main Dish " + name );
   }

   void onDiet() {
      System.out.println("Sorry, I have to refuse it! ");
   }
}