CS 124 daily lessons mix text, interactive walkthroughs, video content, and small practice and homework problems.

Each one brings you one step closer to mastering the basics of computer science and programming. And the course staff will accompany you every step of the way, to ensure that you are not alone.

Fall 2022

10/03/2022: Data Modeling 1

This lesson puts our new abilities with objects to use modeling a real-world system.


Next we'll continue understanding Kotlin objects by exploring companion objects.

Next we'll continue understanding Java objects by exploring the static keyword and its implications.

09/29/2022: Encapsulation

In this lesson we'll investigate how to enable encapsulation through visibility modifiers and setters and getters.

09/28/2022: Constructors

Our next lesson examines what happens when objects are created.

09/27/2022: Objects, Continued

Let's continue our discussion of objects by examining object methods.

09/26/2022: Introduction to Objects

This lesson begins a new topic: objects.


Let's explore a bit of programming internals, specifically your code is tranformed before it is executed in a process known as compilation.

Let's explore a bit of programming internals, specifically your code is tranformed before it is executed in a process known as compilation.

09/22/2022: Practice with Collections

Let's get a bit more practice with collections, those basic data structures that are so useful.

09/21/2022: Maps and Sets

Let's look at two more very useful collections: maps and sets.

09/20/2022: Lists and Type Parameters

Next we'll learn how to use lists, a linear data structure but one that is a bit more useful than the arrays that we've been working with so far.

09/19/2022: Imports and Libraries

This lesson may be the most important of the entire semester, since it shows you how to use other people's code!

09/16/2022: Multidimensional Arrays

This lesson expands our ability to work with sequential data into multiple dimensions!

09/15/2022: Practice with Strings

Let's reinforce what we know about strings by working with a few more problems together!

09/14/2022: null

How many problems can nothing cause? Quite a few! We'll learn more about the nothing that is a huge problem in this lesson.

09/13/2022: Algorithms and Strings

Our next lesson is on algorithms and strings, and gives us a bit more practice with both.

09/12/2022: Strings

Next we meet a new type of data and our first example of an object.

09/09/2022: Functions and Algorithms

In this lesson we'll explore the connections between functions and algorithms.

09/08/2022: Practice with Functions

Let's pause for a bit more practice with functions before we continue our journey together.

09/07/2022: More About Functions

Next we'll continue discussing functions and introduce several common algorithm patterns.

09/06/2022: Errors and Debugging

Let's examine errors, debugging, and maintaining a healthy mindset as you learn to work with computers.

09/02/2022: Functions

As we begin writing algorithms, let's stop and discuss how to organize our code into reusable units called functions.

09/01/2022: Practice with Loops and Algorithms

In this lesson we'll pause for more practice with loops and algorithms, including several chances to get practice solving real problems.

08/31/2022: Algorithms

Next we'll pull together everything we've learned so far and use our new skills to start solving real problems. Or, put another way, we'll start designing algorithms.

08/30/2022: Loops

In this lesson we'll cover our last core computer capability: the ability to repeat something multiple times, very quickly.

08/29/2022: Arrays

Let's learn about our first data structure: arrays, which put data values in order.

08/26/2022: Compound Conditionals

Next we'll examine how to make our conditional statements a bit more complex, allowing us to make more interesting decisions based on data in our programs.

08/25/2022: Conditional Expressions and Statements

One of the things that makes computers so powerful is their ability to make decisions. We'll explore that capability in our programs in this lesson.

08/24/2022: Operations on Variables

Our journey continues as we examine how we can manipulate the data stored by variables in our programs.

08/23/2022: Variables and Types

Let's begin our journey in computer science by presenting two of the basic building blocks of computer programs: variables and data types.

08/22/2022: Welcome to CS 124

Welcome to CS 124! We're excited to join you as you start your journey in computer science and programming. Today!