How to Create a Supermarket Billing System in Java Using OOPS Concepts

public class Supermarket {

    String name;
    double mrp;
    boolean discountApplied;
    double discountPercent;

    // Default Constructor
    Supermarket() {
        name = "Unknown";
        mrp = 0.0;
        discountApplied = false;
        discountPercent = 0;
    }

    // Constructor Overloading (without discount)
    Supermarket(String name, double mrp) {
        this.name = name;
        this.mrp = mrp;
        this.discountApplied = false;
        this.discountPercent = 0;
    }

    // Constructor Overloading (with discount)
    Supermarket(String name, double mrp, boolean discountApplied, double discountPercent) {
        this.name = name;
        this.mrp = mrp;
        this.discountApplied = discountApplied;
        this.discountPercent = discountPercent;
    }

    // Method: Billing (no parameters)
    void Billing() {

        double finalPrice = mrp;

        System.out.println("Item Name: " + name);
        System.out.println("MRP Price: ₹" + mrp);
        System.out.println("Discount Applied: " + discountApplied);

        if (discountApplied) {
            double discountAmount = (mrp * discountPercent) / 100;
            finalPrice = mrp - discountAmount;
            System.out.println("Discount Percentage: " + discountPercent + "%");
        } else {
            System.out.println("Discount Percentage: 0%");
        }

        System.out.println("Final Price: ₹" + finalPrice);
        System.out.println("-----------------------------");
    }

    // Method Overloading (optional usage)
    void Billing(boolean discountApplied, double discountPercent) {
        this.discountApplied = discountApplied;
        this.discountPercent = discountPercent;
        Billing(); // reuse main method
    }

    // Main Method
    public static void main(String[] args) {

        // Object without discount
        Supermarket item1 = new Supermarket("Rice", 100);
        item1.Billing();

        // Object with discount
        Supermarket item2 = new Supermarket("Oil", 200, true, 10);
        item2.Billing();

        // Another example
        Supermarket item3 = new Supermarket("Sugar", 50, false, 0);
        item3.Billing();
    }
}

Output