CS50x 2026 - Lecture 1 - C

All right, this is CS 50, and this is week one, our second week together, and you'll recall that last week, week zero, we focused on scratch ultimately this graphical programming language by which you can drag and drop puzzle pieces that interlock together only if it makes logical sense to do so. And many of you had actually probably played with that

in like middle school or even prior at some point, but for our purposes, the goals of Scratch were to give us sort of a mental model for some fundamental constructs that we're going to see again and again today in C in a few weeks in Python. and even thereafter, and those include things like functions and return variables and

arguments and variables and loops and conditionals and more. And so even if today feels like a bit of a fire hose such as that pictured here, appreciate that a lot of today's ideas are exactly the same as last week's ideas. It's just that the syntax is going to change. It's going to look a little different.

It's going to look a little scarier. It's going to be harder to sort of memorize except with practice will come that muscle memory, but the ideas ultimately are going to be the same. And indeed this is, if unfamiliar, MIT down the road has a tradition of hacks whereby students once a year do something fairly crazy and at this point

they happen to connect an actual working uh drinking fountain to an actual fire hydrant, and the sign there, very pixelated, says Getting an education from MIT is like trying to drink from a fire hose. And that's indeed how computer science, how programming, how CS 50 will sometimes feel, but realize that what's going to be ultimately most important is not where you.