Derive an Employee class from the Person class. The Employee class should add the following properties:
1. Salary
2. Mailing address
In addition, the Employee class should implement the
3. Retrieve amount due
4. Add to amount due
5. Payment address
In other words, the payment address should be the mailing address of the employee. In order to make this work right, you will need to allocate an internally protected state variable that keeps track of the amount of money due. This state variable will obviously be modified by the functions defined .