CS50

Live from Harvard University on Wednesday, September 3, at 1:30 PM EDT, this is CS50's first lecture of Fall 2025, aka Week 0, on:

Computer Science. Computational Thinking. Problem Solving: Inputs, Outputs. Representation: Unary, Binary, Decimal, ASCII, Unicode, RGB. Abstraction. Algorithms. Running Times. Pseudocode. Scratch: Functions, Arguments, Return Values; Variables; Boolean Expressions, Conditionals; Loops; Events; Threads.

Open to anyone online. Or register to attend in person at cs50.ly/attend. This lecture will become part of CS50x 2026 on edX in January 2026.

Convert to own time zone at time.cs50.io/20250903T133000-0400/20250903T161500-….

On Zoom at cs50.zoom.us/meeting/register/_wovJOJ2R0aIUDHQFNH2….

On YouTube at youtube.com/live/6px2ii_x52A.

1 month ago | [YT] | 1,274



@pointer333

CS50 is absolutely the #1 course for getting started in CS. When my 2020 class ended, I literally cried. I felt like part of the family. And my eyes were opened to the way CPU and memory work. I wish we could get a part 2!

1 month ago | 32

@walkslikewater

Loving the CS50 suite of courses. Got to week 7 of CS50x and completed it, then on a recommendation, started CS50p. Currently on week 8 and going to complete it before going back to x. I highly recommend these courses if you're interested in computer science or programming in general. They can be difficult at times but when you get that 'ahah' moment, it's an amazing feeling

1 month ago | 10

@mary_njuguna

Started CS50X in March 2025 it was quite an adventurous journey. Super proud of myself for finishing and taking and finishing CS50W afterwards. If you are just starting out, know that with discipline, determination and great deal of patience with yourself you can do this. This was my first course ever in tech and now I am studying AI and ML to practice Full stack AI engineering. So yes YOU can! 💪

1 month ago (edited) | 6

@christopheanfry

The best experience ever!!! Just had my certificate almost a year ago. An unforgettable journey!!! Thanks cs50

1 month ago | 1

@Tryhellojs

excited to start my first live class in programming ever for the last 5 year i am on the field but i learned nothing from it. really excited

1 month ago | 1

@plagarium

Let's go! Brazil is here 🇧

1 month ago | 1

@jagal6880

Do these get recorded and stay uploaded?

1 month ago | 1

@KawsarAhmed-xd4jg

Absolute GOAT (period)

1 month ago | 0

@Tryhellojs

From the city of joy

1 month ago | 0

@Innoodrr

1 month ago | 0

@Tryhellojs

I purposefully didn't the watch the latest uploaded cs50x 2025 class, since i can become part of the latest batch currently doing cs50p

1 month ago | 0

@AhnafShakilNabid

@cs50 I saw 1st and 2nd lecture of last cs50 in edx. But now i want to join that new one. Besides, can anybody tell me how to admit in Harvard for graduation? (Basically I am not from US, I'm from Bangladesh)

1 month ago (edited) | 0