Design Patterns: Extend Functionality without Modifying Existing Code using OCP

Problem Statement:

A lab to follow the OCP principle while doing your code in C#.

• Create a C# class named Invoice that calculates invoice amounts.
• Extend the Invoice class to support different invoices (e.g., DomesticInvoice, InternationalInvoice) .
• Implement the new invoice types without modifying the original Invoice class code.
• Use the Program class to demonstrate the usage of DomesticInvoice and InternationalInvoice classes for calculating invoice amounts.

Lab Objective:

Upon completion of this lab, you will be able to:

• Understand the Open-Closed Principle (OCP) of software design.
• Capability to add features without changing the current code directly.
• Proficiency in developing and deploying inheritance-based C# solutions for handling various invoice types.

Prerequisites

You should install the following software on your machine:

• VS Code or Visual Studio
• .NET SDK