Lists Practice

For this session, practice using List objects in C#.

1. Complete the basic practice exercises
2. Work on any of the various challenges from the previous session
3. Try to complete the more difficult challenges below

Bonus Challenge 1: ASCII Art Animation

Create a new Repl, and in it, create an ASCII art animation. When the program runs, it should repeatedly cycle through the frames of an animation. The end result should look something like this:

Here are some things that may help accomplish this:

• A List of verbatim literal strings, each with one frame of the animation
• The Console.Clear method to clear the console before drawing each frame
• An infinite while loop, along with a variable to track the current frame for the animation (i.e., the spot in the List of strings)
• The Thread.Sleep method to add time between each frame
• Some way to go back to the first frame of the animation after the last frame has been reached

Bonus Challenge 2: A List of Lists

Sometimes, it makes sense to represent data as a List of Lists in C#. This is sometimes referred to as a 2D (two-dimensional) collection.

For example, imagine a school attendance tracker. A teacher would like to keep track of which students are absent each day. For a given day, there is a List of string objects, each of which contains the name of an absent student. All of these lists are stored in another List, which contains all of the information across all of the days.

The type of the List, instead of being something like int or string, is List<string> because the list contains List objects! It ends up looking like this:

List<List<string>> attendanceDays = new List<List<string>>();

Create a program that allows a teacher to keep track of the absences across multiple days. This should be a menu-based application. The teacher should be able to do the following:

Add a new daily entry to the main List

Create a new List<string object for the current day, and add it to the List<List<string>>.

View the entire list of absences

Print out each day of absences. Note that if the list is empty for a given day, "(no absences)" should be printed.

It should end up looking something like this:

--Day 1--
Lucy
Shan
Darius

--Day 2--
Shan

--Day 3--
Mario
Lucy

--Day 4--
(no absences)

--Day 5--
Darius

Find the total number of absences for a given student

Loop through each day of absences, and keep track of how many times the student's name appears.

Side-Note: Wikipedia List of lists of lists

There is an impressively comprehensive list on Wikipedia that contains lists of other lists.