SLOG for CSC104

CSC104 is one of the courses that I actually enjoyed a lot in UofT, and so far I’ve been getting decent marks. Hopefully the final exam goes well too. 

I first became familiar with modules when I wrote my Maths Exploration essay on RSA encryption in IB. This wasn’t a topic covered in class and I spent a lot of time researching before actually starting the essay. To convert a relatively small number from base 10 to base 2, we can simply decompose the number into a sum of exponentials of 2, and then put these exponentials into a list where we assign 1 for an existent number in the exponential sequence, and 0 for an absent number, arranging from the biggest to the smallest. The binary representation of a number can get quite long for bigger numbers, but since there’re only two options, it might be easier for computers to calculate. It’s very impressive when you think of how much computers have progressed and changed over decades, but this basic system language always remained the same.

We learned about Fibonacci sequence this week, and this somehow reminded me of Pascal’s triangle, another mathematical sequence that involves using a triangle to deduce the following numbers. However, since the calculation of Fibonacci sequence in DrRacket causes repetition every time we compute it from a standard function, the lecture files demonstrated ways to reduce the amount of repetition by converting the results into a special type of list called pair, enabling us to compute numbers that are of higher order in the Fibonacci sequence. I also found out that DrRacket runs faster when I increase the memory limit shown at the bottom right corner of the panel. Honestly though, I never knew mathematical calculations that look simple would take computers this much time and memory, this is probably why web calculation companies like Wolfram Alpha became so useful. 

The course is great in how the prof and TA’s are really accessible, and it’s set up on Piazza.com as well. However I haven’t really got a chance to utilize these resources just because I’ve been able to solve questions either myself or just through some Googling. If I encounter any problem in the future, I’ll definitely try going to the office hours!

Something new I learned through the encryption assignment is the filter function, one type of “function inside a function”. In a filter function, we need to write a local statement with up to 2 variables, and filter out items in a list that don’t meet certain characters also defined in the local statement. This is useful because with a filter function, we don’t have to repeatedly write similar codes when one of the two variables changes, the function itself does it for us. When writing the assignment, I found the first part mostly a review of what we learned in class, and the second part a bit more challenging, a lot of research was required to complete the functions. However in the end I got all the tests passed and I really enjoyed the process.

In a lecture last week we learned about the application of repeating functions, which turned into a cool animation. The whole material is a little bit confusing, I'm just dropping down a few thoughts on this here. To start, we build on a function called “big-bang” in the picturing programs, in the format of “on-tick”, which defines the interval of rotation, and “to-draw”, which defines the image being shown.To reduce the lag betweens cycles of rotation, we also had to modify the background of the image, but I didn’t completely understand what caused the lag and why. However, I thought this was interesting as the “big-bang” function is kind of similar to the “timer” function in the older Windows programming language I learned about in high school. A timer basically sets an interval for a repeating action, and this way it saves the time to write a repeating function from scratch. I think the two programming languages focus on different aspects of writing computer programs, but there’s still so much more to explore in DrRacket!

It’s not until before the first midterm last Friday that I really started looking into writing functions in DrRacket. We learned about various data types, header and body, using check-expect to create functions step by step, but we never wrote one ourselves in a quiz or an assignment. I looked over all the lecture files as well as past exams when I studied for the test, and started to find writing functions really interesting. A well-designed one saves a lot of time and work when we program codes in DrRacket. I really hope there’ll be more lecture materials on writing functions. 

I was always interested in how computer softwares and hardwares work together when I was little, and I think that interest never faded away although I chose another field of study in university (I’m in Pharmacology&Toxicology). I’m also very interested in new technology products just as many other people, and I spend time reading about them on websites like Indiegogo. Hopefully I’ll get more chances exploring computer sciences. :’)