Week Five - Scopes and Namespaces

This week's first lecture was about how to solve the cheese problem using only three stools. I am really happy that the solution was discussed in class, because I think it would be much hard if I was to trace and understand that recursive code myself. After the lecture on Monday, I finally fully understood the four-stool algorithm described in the assignment sheet. 

The second lecture was about scopes and namespaces. I really enjoyed the topic and we did some really interesting examples in class. One thing I found Java very special is that everything is a reference to a memory address somewhere in the computer. Surprisingly, it is also possible for two module to have the same function name. But if both module is imported by the user, and if he/she wants to use the method, they must prefix it with the module name. In the lecture, we also talked about how to search for names: it will first look in the inner most scope (e.g. if you define a function inside in a function, python will first look in there), then it will look in the enclosing scope, then the current module or __main__, finally it will look in the build-ins. If they can't find the name in the build-in, an error will be raised. A name can also be declared nonlocal or global and if you don't put anything infront of the name, it will be local (which is the default). Finally, the example we discussed in class was quite tricky, I would probably did most of it wrong if I was tracing it myself. Namespaces and scopes is a new topic, I think I need to spend more time on the concept in order to grasp the concept.

The lab this week is about recursion, the handout first asked to trace two recursive functions. I found that pretty helpful, because I knew how to trace it in my head, but I was unsure the format of writing it down on paper. The programming part of lab went surprising well this week, me and my partner figured both method out. And we even tried some extra problems. I think I am improving in writing recursive functions, but I still need more practice to master recursion.