Weeks
Fifteen Mondays
Each card opens a week: what to watch before class, objectives, notes, the wow moment, the lab and where to go deeper.
Foundations: Bits and Thinking
0 1- 01Foundations Sep 21
Welcome: What This Course Is and How It Works
The map of the semester, how a Monday works, what you need before next week, and the one question the whole course answers: how does a machine that only knows 0 and 1 do everything?
Notes ready - 02Foundations Sep 28
Everything Is Bits: Representation, Algorithms and Scratch
CS50 Week 0, live: how 0 and 1 become numbers, letters, colors and sound; what an algorithm is and why some are dramatically faster; and the five ideas of every programming language, built step by step in Scratch.
+ lab Notes ready
The C Language
int main(void)- 03C Oct 5
C: Source Code, the Compiler and Your First Real Programs
From Scratch blocks to text: how source code becomes machine code, and the C you need to write programs with variables, input, conditions, loops and functions.
+ lab Notes ready - 04C Oct 12
Arrays, Strings and the Command Line
What the compiler really does in four steps, how to debug instead of guessing, and the first data structure: arrays, including strings, which are arrays of characters. Plus command-line arguments and a first taste of cryptography.
+ lab Notes ready
Algorithms, Memory and Data Structures
*p → &x- 05Algorithms & Memory Oct 19
Algorithms: Searching, Sorting and Big O
Linear and binary search, three ways to sort, and a language for comparing them: Big O, Ω and Θ. Plus structs, and recursion, which is a function that calls itself.
+ lab Notes ready - 06Algorithms & Memory Oct 26
Memory: Pointers, the Heap and Hexadecimal
The week that takes the hood off. Addresses, pointers, why a string was a char* all along, malloc and free, the stack and the heap, segmentation faults, and files and images as bytes.
+ lab - 07Algorithms & Memory Nov 2
Data Structures: Linked Lists, Hash Tables and Trees
Now that you can allocate memory, you can build your own structures: linked lists that grow, hash tables that find things in constant time, binary search trees, tries, stacks and queues. And the trade-offs between them.
+ lab - 08Algorithms & Memory Nov 9
Midterm Exam
Written, in class, covering weeks 1–7: representation, algorithms, C, arrays and strings, searching and sorting, memory and data structures. The official date and room are announced by the faculty.
Exam Notes ready
Python, AI and Data
SELECT *- 09Python · AI · SQL Nov 16
Python: The Same Ideas in a Tenth of the Lines
Every C program you wrote, rewritten in Python: no types to declare, no semicolons, no memory to free, and a library for everything. What you gain, what you give up, and how to learn any new language in a day.
+ lab - 10Python · AI · SQL Nov 23
Artificial Intelligence: How It Actually Works
From decision trees and minimax to machine learning, neural networks and large language models. What a transformer does with your prompt, why models hallucinate, and how to use AI well as a programmer.
+ lab - 11Python · AI · SQL Nov 30
SQL: The Language of Data
Flat files and their limits, relational databases, and SQL: creating tables, inserting, selecting, joining, indexing. Plus the two bugs every backend engineer must know: race conditions and SQL injection.
+ lab
The Web and the Internet
</>- 12Web Dec 7
The Web: HTML, CSS and JavaScript
What happens when you type a URL, and how a page is built: HTML for structure, CSS for style, JavaScript for behavior. By the end of the lab you have a page that reacts to the user.
+ lab - 13Web Dec 14
The Internet, Hardware and Security
Behind the wires: how packets cross the planet, what a CPU and memory hierarchy really are, and cybersecurity for people who now write code: passwords, hashing, encryption, phishing and the attacks you learned to cause in weeks 4, 6 and 11.
+ lab
Humans, Systems and Your Project
v1.0- 14HCI & Projects Dec 21
Human–Computer Interaction and How Software Gets Built
Software is used by people and built by teams. Usability principles you can apply to your project this week, and a tour of how industry ships software: Git branches, code review, tests, CI, and the roles on a team. The lab is a project workshop.
- 15HCI & Projects Dec 28
Demo Day and Where Computer Science Goes Next
Every student demos their project live. Then a short last lecture: what you now know, what comes next in the curriculum and in the field, and how to keep learning after the course ends.