This is CS50x 2025, an older version of the course. See cs50.harvard.edu/x/2026 for the latest!

This is CS50

CS50’s Introduction to Computer Science

OpenCourseWare

David J. Malan
malan@harvard.edu
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Zoom Meetings

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

CS50 Educator Workshop
Gallery of Final Projects
What’s new for 2025?

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

Artificial Intelligence

Additional Practice

Final Project
Gallery of Final Projects
Seminars

Academic Honesty
CS50 Certificate
FAQs
Gradebook
Staff
Syllabus

Apple TV
edX
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Harvard Extension School
Harvard Summer School
Roku new
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
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Stack Exchange Q&A
Telegram
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X Account
X Community
YouTube

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

Weeks

Week 0
Week 1
Week 2
Week 3
Week 4
Week 5
Week 6
Week 7 🎃
Week 8
Week 9
Week 10

Artificial Intelligence