This is CS50x 2024, an older version of the course. See cs50.harvard.edu/x/2025 for the latest!

This is CS50

CS50’s Introduction to Computer Science

OpenCourseWare

David J. Malan
malan@harvard.edu
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CS50x Puzzle Day 2025new

CS50.ai
Ed Discussion for Q&A
Visual Studio Code

CS50 Educator Workshop
CS50x Puzzle Day 2024
Gallery of Final Projects
What’s new for 2024?

Week 0 Scratch
Week 1 C
Week 2 Arrays
Week 3 Algorithms
Week 4 Memory
Week 5 Data Structures
Week 6 Python
Week 6.5 Artificial Intelligence
Week 7 SQL
Week 8 HTML, CSS, JavaScript
Week 9 Flask
Week 10 Cybersecurity

Additional Practice

Final Project
Gallery of Final Projects
Seminars

Academic Honesty
CS50 Certificate
FAQs
Gradebook
Staff
Syllabus

Apple TV
edX
Google TV
Harvard Extension School
Harvard Summer School
YouTube

Manual Pages
Style Guide

Status Page

Communities
Bluesky
Clubhouse
Discord Q&A
Ed Q&A
Facebook Group Q&A
Facebook Page
GitHub
Gitter Q&A
Instagram
LinkedIn Group
LinkedIn Page
Medium
Quora
Reddit Q&A
Slack Q&A
Snapchat
SoundCloud
Stack Exchange Q&A
Telegram
TikTok
Threads
Twitter Account
Twitter Community
YouTube

Courses
CS50x
CS50 AI
CS50 Business
CS50 Cybersecurity
CS50 for Lawyers
CS50 Python
CS50 R
CS50 Scratch
CS50 SQL
CS50 Web

Weeks

Scratch
C
Arrays
Algorithms
Memory
Data Structures
Python
SQL
HTML, CSS, JavaScript
Flask
Cybersecurity

Artificial Intelligence