CS50 - week 1, continued - some More C

CS50 - week 1, continued - Some more C

lecture 2

So, this is still week 1, apparently, despite it being lecture 2 and problem set 2. o well... This lecture starts with some simple loop examples that are easier versions of problem set 1's mario problems (,which is why I watched lecture 2 before doing problem set1, Which I kept doing. In hindsight this is only useful up to problem set 4). Some debugging help is shown here as well, like some commands programmed by the cs50 team, but honestly it never gave me any useful feedback and I always debugged by overloading on printf statements.

Afterwards the lecture goes a bit deeper in the basic data types in C: int, float, char, string (which actually doesn't exist), and so on. Some functions made by the cs50 team were also shown to get user input and it's also shown how strings are just a row of chars. The relation between int and char (ASCII) was also shown. The problem set involves toying with chars and strings in the form of cryptography

problem set 2

three problems this week:

Caeser.c (easy)

Make a program that, given a number and a word, replaces every letter in the word with another further in the alphabet by that number.

so ab and 2 gives cd

idiot and 3 gives lglrw

this wasn't too bad.

Viginere.c ("easy")

That caeser is the oldest known way to encrypt a message, by "rotating" all letters across the alphabet. Once you are aware of it, it is ofcourse easy to break, so a slightly upgraded encryption method was used later (still centuries ago). The Viginere rotates your to be encrypted message by another word (the cipher). It is just a slight upgrade from the Caeser method and I already got the code from that one, so how hard could this be? well, as the quotes around "easy" show, this was not easy. It took me 2 hours to do caeser and another 3 to upgrade it to the viginere method for a total of 5 hours.

Crypt.c (hard)

I admit, this was hard. So hard in fact that I skipped it for later as I was getting nowhere.