ProductBilling.java

public class ProductBilling {
    public double calculateBill(double price1) {
        System.out.println("Billing for 1 product...");
        return price1;
    }
    public double calculateBill(double price1, double price2) {
        System.out.println("Billing for 2 products...");
        return price1 + price2;
    }
    public double calculateBill(double price1, double price2, double price3) {
        System.out.println("Billing for 3 products...");
        return price1 + price2 + price3;
    }
    public double applyDiscount(double totalBill, double discountPercent) {
        double discount = (totalBill * discountPercent) / 100;
        return totalBill - discount;
    }
}