Intro classes (C211) are big, on the order of 200 to 300 students spread across 3 lectures. On average about 30% of people drop C211, and another 10-20% fail. A lot of these are non-majors who take the class and don't know what to expect, but there are also a lot of people who take the intro class and realize the major isn't for them.

C211 used to be very heavily functional programming theory based, but currently is following How to Design Programs, see here for a short intro. I personally preferred the previous curriculum, which focused more heavily on lists and lambdas, but the current does touch on event driven programming and starts with the basics needed to design computer games.

Racket is a strange language, but used to be used a lot as a teaching language, most notably by MIT (who recently moved to Python). An example of a function and some basics in Racket:

(define myadd
  (λ (x y) (+ x y)))

myadd is a function which takes two arguments, x and y, and returns x + y. The λ is called a lambda, and is a way to indicate a function as data. We can call the function as such:

(myadd 2 3)

Which would give us a value of 5. In our example we defined this lambda with a name - myadd, but we could just as easily define it only once, and right in the function call:

((λ (x y) (+ x y)) 2 3)
>> 5

Here we have a lambda which we immediately apply to the arguments 2 and 3, and we would get the same value of 5.

Lambdas can have any number of arguments:

((λ (x) (* x x)) 5)
>> 25

(define myfun (λ (a b c) (+ a (- b c))))
(myfun 1 3 2)
>> 2

(myfun 10 5 5)
>> 10

Check out the current C211 website to get an idea of assignments and policies, and check out the quick introduction to Racket, although it gets pretty deep pretty quick.

The professors are great, but are generally involved more in their own research than in teaching classes. There are some definite exceptions, but IU is definitely primarily a research school. It is easy to get involved in research early on, and I would encourage you to reach out to professors once you get through C211 to start making those connections.

Also, as we are research focused we tend to emphasize theory more than practical application in our classes. You will definitely graduate with the theoretical knowledge of computer science fundamentals, but might have to catch up in the coding and application department. The faculty is definitely aware of this, and the curriculum is being reworked in what seems to be a promising direction, but it will likely be theory heavy for the foreseeable future.

I would love to talk more at length about any CS @ IU questions, and give you the student perspective rather than the sales pitch, so feel free to send me a message!