docs: add README

README.md

@@ -0,0 +1,191 @@
+# Sixth Assignment — Exceptions and Files
+
+## Introduction
+
+In this assignment, you will practice working with:
+- File reading and writing
+- Exception handling
+- CSV data processing
+- Validation of user/file input
+- Basic report generation
+
+The goal is to build a small sales report system that reads product and order information from CSV files, validates the data, calculates totals, and generates a final report file.
+
+This assignment focuses heavily on using exceptions and file operations correctly while keeping the program stable even when invalid data exists in the input files.
+
+---
+
+# Objectives
+
+By completing this assignment, you should be able to:
+
+- Read data from CSV files using Java file handling tools
+- Parse and process text-based data
+- Use exception handling (`try-catch`) to manage invalid input safely
+- Validate numeric and logical data
+- Skip invalid rows without stopping the entire program
+- Generate and save reports into output files
+- Organize code into multiple classes and methods
+- Use Git and GitHub/Gitea workflows professionally
+
+---
+
+# Tasks
+
+## Part 1 — Load Product Data
+
+Implement the `loadProducts()` method in `Main.java`.
+
+Requirements:
+- Read product data from `products.csv`
+- Each line follows this format:
+
+```text
+[productId],[name],[price]
+```
+
+Example:
+
+```text
+1,Apple iPhone 16,999.99
+```
+
+Notes:
+- The product file data is guaranteed to be valid.
+- Every line contains exactly two commas.
+- No additional validation is required for this file.
+
+You should:
+- Read each line
+- Parse the values
+- Create `Product` objects
+- Store them inside `productCatalog`
+
+---
+
+## Part 2 — Process Order File
+
+Implement the `processFile()` method in `ReportGenerator.java`.
+
+The order details file follows this format:
+
+```text
+[productId],[quantity],[discountPercent]
+```
+
+Example:
+
+```text
+1,2,10
+3,5,25
+```
+
+---
+
+### Validation Rules
+
+A line is considered invalid if:
+- `quantity` is not a valid integer
+- `discountPercent` is not a valid integer
+- `quantity <= 0`
+- `discountPercent` is outside the range `0–99`
+- The `productId` does not exist in `productCatalog`
+
+If even one field is invalid, the entire line must be skipped.
+
+---
+
+### Important Requirement
+
+You are strongly encouraged to use:
+- `try-catch`
+- exception handling
+- `NumberFormatException`
+
+to safely process invalid rows without terminating the program.
+
+The program should continue processing the remaining lines even if some rows are invalid.
+
+---
+
+### Calculations
+
+For every valid row:
+
+```text
+subtotal = quantity × productPrice
+
+discountValue = subtotal × discountPercent / 100
+
+finalCost = subtotal - discountValue
+```
+
+Update the following totals:
+
+- `totalQuantity`
+- `totalFinalCost`
+- `totalDiscountValue`
+- `totalInvalidLines`
+
+---
+
+## Part 3 — Generate Report
+
+Implement the `saveReport()` method.
+
+The generated report should contain:
+- Total quantity
+- Total final cost
+- Total discount value
+- Number of invalid lines
+
+Example:
+
+```text
+===== SALES REPORT =====
+
+Total Quantity: 25
+Total Final Cost: 1520.50
+Total Discount Value: 210.75
+Invalid Lines: 3
+```
+
+Save the report into an output file.
+
+---
+
+# Submission ⌛
+
+Before submitting:
+
+- Add your mentor as a contributor to the repository
+- Create a `develop` branch for implementation
+- Use Git regularly with meaningful commits
+- Push all code to the remote repository
+- Push the answers/documentation file if required
+- Create a Pull Request from `develop` → `main`
+
+---
+
+# Additional Resources 📚
+
+## TA Explanations
+- 
+
+## Java File Handling
+- https://docs.oracle.com/javase/tutorial/essential/io/
+
+## Java Exceptions
+- https://docs.oracle.com/javase/tutorial/essential/exceptions/
+
+## Scanner Class
+- https://docs.oracle.com/javase/8/docs/api/java/util/Scanner.html
+
+## Try-Catch in Java
+- https://www.w3schools.com/java/java_try_catch.asp
+
+## Git Branching
+- https://git-scm.com/book/en/v2/Git-Branching-Branches-in-a-Nutshell
+
+## CSV Basics
+- https://en.wikipedia.org/wiki/Comma-separated_values