week 4

This week we have mainly learned Recursion, which is basically use the same function to continue doing some work until the end. This week the prof also introduced the function called turtle which is really fun, seeing and understand the process how it actually worked and processed. However, it was a little bit hard when it was the first time to understand a recursion which was totally a new thing to me. However, Recursion is really important in CS programming and in the first assignment, I plan to look through it in more detail and try to do more practices on it and get used to use Recursion and import it into my programming works. During the lab this week, the unittest is still a problem which I had no idea how to do it. However, the page of python was pretty helpful and provided me a lot of suggestions to do it. The TA was patient as well, helping us through several times to help us to understand it. There are a lot of assignments going on and also the tests, so I did not have a chance to start it yet, but I will try to work on it sometime during the weekend. 

Object-orientated programming

OOP

All kinds of programming languages including Java, C++, C, and python, which we are currently studying are all object-oriented programming languages. Almost all the languages that are popular now are OOP, which has a great advantage based on the way how it organize the models of the objects. Basically, OOP is organized by encapsulation, inheritance, and polymorphism.

Since OOP is ‘object-orientated’, it can break the abstract and complicated parts into smaller pieces of objects to break down issues.

We have not really learned about ‘encapsulation’ and ‘polymorphism’ yet, but basically, if my interpretation is right, ‘encapsulation’ is more like a box that prevent the access of codes and data by the other data. This property helps to share the codes both publicly and privately, which means  showing people codes that the programmer want them to see and hiding the private ones from people to prevent them from modifying them. Apart from that, ‘polymorphism’ refers to using the same name of the object while doing different things. We have not learned this yet and I am not sure about this part, maybe my interpretation is wrong, but it is my guess.

For ‘inheritance’, we just learned it yesterday, which is to make subclasses of the basic classes. Based on the example in class, the subset of exceptions have special-exception and extreme-exception, which is the subset of class special-exception. That is to say, exception has all the properties extreme-exception and special-exception has. Thus, exception can basically include everything, yet special-exceptions might only contain the strings, and extreme-exception only contains ints in strings. In other words, each subclasses of classes has their own unique properties, and the basic properties from the original class was inherited to all the subclasses.

In conclusion, we have only touched the basic stuff of OOP now, which means that we will be able to have more ideas about ‘encapsulation’ and ‘polymorphism’ in the future. The comprehension of inheritance might not be appropriate as well, but we are learning it now, so more examples in classes and exercises might help us more on interpreting it.