Adding the Interface

The child class Food extends the parent class. It uses super to use the parent's constructor and the parent's display method.

class Food extends Goods
{
  double calories;

  Food( String des, double pr, double cal)
  {
    super( des, pr );
    calories = cal ;
  }

  void display()
  {
    super.display( );
    System.out.println( "calories: " + calories );
  }
}