Write a program in C++ / Java using method overriding to calculate electricity bills for Residential and Commercial customers. Create a base class…

Java, with the base method overridden in each subclass; the call goes to the object’s own class at run time:

class Customer {
    double calculateBill(int units) {
        return 0;
    }
}

class Residential extends Customer {
    @Override
    double calculateBill(int units) {
        return units * 6;   // 6 TK per unit
    }
}

class Commercial extends Customer {
    @Override
    double calculateBill(int units) {
        return units * 10;  // 10 TK per unit
    }
}

public class Main {
    public static void main(String[] args) {
        Customer residential = new Residential();
        Customer commercial = new Commercial();
        int units = 150;
        System.out.println("Residential bill: " + residential.calculateBill(units) + " TK");
        System.out.println("Commercial bill: " + commercial.calculateBill(units) + " TK");
    }
}

Output for 150 units: Residential bill: 900.0 TK, Commercial bill: 1500.0 TK.

— rhs