Project: Overlapping Appointments

Agenda is our first project with user-written classes.

Overview

In this project you will

• Create a class Appt (short for “appointment”) that represents a single appointment with a start time, an end time, and a description. For example, you might create an Appt object to represent CS 210 lecture from 10am to 11:20am on January 7, 2025.

  • The Appt class will make use of the datetime class from the Python library, which you will import.

  • Each Appt object will contain three instance variables, also known as fields. Two of these, the start time (e.g., 10:00am on January 7, 2025) and end time (e.g., 11:20am on January 7) will be represented by datetime objects. The third instance variable will be a description represented as a str object.

  • You will write several methods for the Appt class. These include magic methods for comparing Appt objects. We will interpret < as before, so that app1 < app2 will mean “the end of app1 is no later than the beginning of app2”.

  • You will write an overlaps method. app1.overlaps(app2) will mean that there is a non-zero overlap in the periods represented by app1 and app2.

  • You will write an intersect method, which creates a new Appt object representing the overlapping portion of two appointments.

  • You will write additional methods for creating and printing Appt objects.

• Create a class Agenda representing a collection of Appt objects. An Agenda object will be a wrapper for a list object. It will have a single instance variable, a list of Appt objects. Many of its methods, like append, will be delegated to corresponding methods of the list it wraps. The point of creating an Agenda class is to alter the behavior of some methods (e.g., customizing the way a list of appointments is printed) and add some new methods.

  • You will write a conflicts method to detect any overlap in two Agenda objects. The result of ag1.conflicts(ag2) will be another Agenda object, containing an Appt object for overlap between any Appt object in ag1 and some Appt object in ag2.

Most of the Agenda project is not complicated or difficult, but you can expect some frustration and time spent because you are using unfamiliar language features. Be sure to correctly use the methods you have defined to simplify other parts of the program (the DRY principle, don’t repeat yourself). For example, when you write the overlaps method of Appt, make use of the < magic method by noting that if app1.overlaps(app2), then neither app1 < app2 nor app2 < app1.

The only tricky bit in the project is making the intersect method efficient. By sorting both Agenda objects ag1 and ag2, you can avoid comparing every Appt in ag1 with every Appt in ag2, which would take time proportional to the product of their lengths.

You will turn in one file, appt.py, containing both class Appt and class Agenda.