A super class Demand has been defined to store the details of the demands for a product. Define a…

class Supply extends Demand
{
    int pproduced;   // quantity produced
    double prate;    // cost per unit

    // parameterised constructor for both classes
    Supply(String id, String name, int d, int p, double r)
    {
        super(id, name, d);
        pproduced = p;
        prate = r;
    }

    // difference between amount of demand and amount produced
    double calculation()
    {
        return (prate * pdemand) - (prate * pproduced);
    }

    // displays all details and the difference
    void display()
    {
        super.display();
        System.out.println("Quantity produced: " + pproduced);
        System.out.println("Rate per unit: " + prate);
        System.out.println("Difference in amount of demand and supply: " + calculation());
    }
}