Saturday, April 29, 2017
AP Computer Science 2016-2017: Recursion & Sorting Algorithms (April)
AP Computer Science 2016-2017:
Recursion & Sorting Algorithms
We are now done with the course! We finished CH10 Inheritance, CH11 Polymorphism, CH19 Recursion and CH20 Searching and Sorting Algorithms! The post on all this is below. First, let's have our Pep Talk again:
AP CompSci Pep Talk 2017
The best way to learn how to code is to watch someone else code and try to do some coding yourself everyday! That's what I try to provide for you in class.
Also, the best way to succeed on the AP CompSci Exam is to read and write code everyday even at home! You should be playing around with repl.it everyday now that we have a server we can use in class and at home!
You also need to get the latest Barron's Review book and read and write a little code in there everyday. You should be reading our textbook power points and trying our lab pdfs everyday!
Just a little advice from your friendly neighborhood CompSci teacher who's been coding for over 40 years!
Ever since Linux came out (1995?), I have always provided my students with a sftp/ssh server they could log into in class and from home. This was a great solution for us as students could work on labs in class, in extra help, in the library and at home. This made our workflow very efficient so that we could do a lot of programming assignments in a short amount of time. I'm used to giving my students a lot of lab time and coding practice everyday!
In recent years, my district has hired out our tech services to some off campus "experts" in IT and Cyber Security. This new "Tech Dept" has found fit, in its infinite wisdom, to change the school's internet firewall in such a way so as not to permit ssh tunnels in or out. My pleas to the contrary falling on deaf ears. So, now my students cannot login from home. I've been struggling with alternate solutions involving Teamviewer, SplashTop and Chrome Remote Desktop just to name a few. These experiments have had varrying degrees of success but still no joy.
This semester I started playing around wih online java IDEs. I tried many and found Cloud9 actually provided an online Ubuntu terminal very much like what we use in class. However, javac is no longer installed and customer service is not very helpful....
cloud9 is free. However, if you want to setup a teacher account, it costs a modest $1 per month.
Why would you pay if it's free? The problem with cloud9 is the registration process. They require a credit card for identification purposes.
Students can join your Team without a credit card if you have a Teacher Account.
Regarding the APCS Labs (Magpie, etc), I still have my local sftp linux server in class for GUI and graphical work.
Most of the work we do all year is more text based, so using https://repl.it or https://c9.io would be fine.
Also, if we want to play with graphics we could use https://www.openprocessing.org/
I'm sticking with repl.it for now as my students are doing well with it and it's easy to share code on my SmartBoard as I teach.
c9 is hard to see on the SmartBoard. You can increase font size in the text editor but not in the terminal???
Actually, you can install default-jdk (openjdk) from the commandline much as you do in a standard Ubuntu terminal with apt-get. Here's an example of some coding I did, https://ide.c9.io/calcpage/rot13
If you want to play with c9 you can make one workspace for the whole year, just make a new directory (aka folder) for each project,
Also, make a "custom workspace" by clicking on the Ubuntu icon. They have different workspaces for c++, python, html website dev, etc.
Your Custom Workspace is basically a plain vanilla install of Ubuntu (virtual machine like Harvard's CS50 uses) that works over a web interface.
So, jdk is not installed. Do this once in the terminal (aka commandline):
sudo apt-get update
sudo apt-get install default-jdk
This installs the latest version of openjdk from the debian repositories which is fine for text based work.
However, we did play around with https://repl.it and found it very useful. Students get their own free accounts. Students can store their work with revision histories. Students get a text editor with syntax completion and syntax color highlights (simple java IDE). Students get an ASCII terminal for output. You can use a variety of programming languages too.
Teachers can get a teacher account where they can set up online classrooms and assignments but I haven't done that. I'm using my account as the students do. Each new project is saved as a separate session. Each session can have multiple files and classes. One thing to watch out for is that the main method has to be in Main.java in the Main class.
Last, but not least, you can share a live instance of any particular revision of any session you want complete with editor, terminal and runner. Here's an example, https://repl.it/GLAC/93
We are now done with the course! We finished CH10 Inheritance, CH11 Polymorphism, CH19 Recursion and CH20 Searching and Sorting Algorithms! Chapters 10+11 were covered with a reading from our text and two take home exams. We've been covering these topics all year! LAB18/CH19 about recursion is covered in the video above. We wrote our own Math class comparing iterative and recursive algorithms. CH20 about searching and sorting was also a reading but it's also covered in the Youtube Wednesday below! We also watched and National Geographic video from 1984: "Miniature Miracle: The Computer Chip." This video is not on Youtube, sorry. I copied to DVD from VHS and show it every year! I used to have it on Youtube, but I was asked to take it down...YouTube Wednesday: Sorting Out Sorting!
Teaching With Technology,
Well, that's all folks,