🧾 Billing System – Java Swing GUI Application

A desktop-based Billing System built using Java Swing that allows users to manage items, calculate totals with tax and discounts, and handle exchange/refund operations.

🚀 Features

• Add, edit, and remove items from the billing table.
• Calculate and display total, tax, discount, and final bill.
• Exchange an item with another or process a refund.
• Non-editable table to avoid accidental changes.
• Interactive GUI for a smooth user experience.

🖥️ GUI Technologies

• Java Swing
• JTable, JTextField, JButton, JOptionPane, and JScrollPane

📦 How to Run

Requirements:

• Java JDK 8 or higher
• Any IDE (e.g., IntelliJ, Eclipse, NetBeans) or command line

Steps:

1. Save the file as BillingSystem.java.
2. Compile and run

Or simply run from your IDE.

🧮 Bill Calculation Logic

• Total = Σ(Item Price × Quantity)
• Tax = (Tax Rate)% of Total
• Discount = (Discount Rate)% on (Total + Tax)
• Final Bill = (Total + Tax - Discount)

🔁 Exchange/Refund Logic

• Exchange: Prompts user to update the item with a new name, price, and quantity.
• Refund: Removes item and shows refund value = price × quantity.

🛠️ To-Do / Enhancements

• Add saving/loading bills from file
• Generate printable invoice
• Add product search and filter
• Add validation messages for inputs