Concrete Methods: Point Card class with State

In this problem, you will create a program that performs sequential point additions and usage on a PointCard instance, and displays the current point balance to standard output after each operation.

Learning Objective: Understand concrete methods that modify fields (state) and learn object state management methods

Create PointCard class to manage point card. Implement two methods for adding points (addPoints) and using points (usePoints), and create program to modify state progressively.