I love GridWorld, the case study for AP Computer Science. I think it makes the course much more authentic in that students experience developing software in a large (compared to what they are accustomed to) and unfamiliar code base.
One of the first labs that we did was the ActorBox lab published as part of the A+ Computer Science curriculum materials. The students knew almost nothing about GridWorld and nothing about object-oriented programming, but they managed to figure out how to add Actors the the World. I introduced this lab as their first day on the job: “welcome to your new software job, here’s a large code base that you didn’t write and you don’t yet understand, figure out how to …”
Since then we have been learning the basics of Java, and now that we understand conditionals and loops, we can finally write interesting software. For the summative lab, I wanted to revisit GridWorld, emphasize the various phases of software development, and have them write a program that would be memorable. Implementing Conway’s Game of Life in GridWorld seemed to be the perfect fit.
I introduced Conway’s Game of Life last week and presented them with some initial requirements. However, I left a lot of the requirements unspecified. Students enumerated their own requirements on Friday and discussed them with me. I wanted them to realize that they needed to specify such requirements as the grid size, how to represent alive and dead cells, when the program finishes, and the time between generations. Students came up with a variety of ways of specifying these requirements with various levels of user specification. Students then started working on their design (flow charts or pseudocode; we haven’t touched on UML yet). This weekend, the were to enumerate their test cases and they will start implementation this week.
Through all of this, I continuously stressed that their requirements and design should be treated as living artifacts and will evolve as they progress through this lab. (I’m a huge proponent of Agile Software Development Methodologies, but that is a subject for another post.)
Since, at this point in the semester, my students are not that familiar with object oriented design, their solutions will be a functional approach and, most likely, inefficient and implemented with brute force. They will get to apply their newly acquired conditional and loop structures. I also think they will better appreciate the upcoming units related to object-oriented design as a result of this experience. In fact, I’m planning on a future lab to be going back and refactoring their Game of Life program.
Here’s the assignment that I posted:
I think this may be my first computer science, related post… cool.