Blog 4


As what we learned in the class, testing is about the process of executing code and comparing the actual results to expected results. If the actual result fit the expected result, then we say the program is successful; however, if the actual result is different from the expected result, there is some problem with your code. There are many kinds of testing, such as unit testing, component testing, integration testing, regression testing, and system testing. In the class 3081, we did a lab which is about testing with cxxTest, which is a kind of unit testing. Unit testing, however, can be defined as an execution of a complete class, routine, or small program that has been written by a single programmer or team of programmers, which is tested in isolation from the more complete system. So as we can see from the definition, cxxTest is a very basic testing skill. Specifically, what we did in the lab is to write the test for a "ReadInput" file, after loading a cxxTest file provided, we try to use it to test ReadInput function, basically, there involved three tests, the first one ensures that the null pointer is returned if no file name is provided, the second one ensures that the null pointer is returned when the name of a non-existent file is passed and the function attempts to access that file, and the third one ensures that when given proper input referring to an existing, readable, filename, the pointer returned is not null. Finally, we modified the "makefile " to include all the test files we just wrote, and run the program to check the testing results. As I mentioned above, cxxTest is a kind of unit testing, which is basic. Thus, this lab is straightforward, but it is definitely a good way to give a general idea of cxxTest. In addition, it helps we to understand the benefit of testing, which we talked about in the lecture that testing improves your confidence that the code is correct, and avoid collateral damaging in fixing bugs. However, to write a good test, there is a long way to go, as we know from Meyer's first principle, when we write a test, we want to make it fail. But as testing can only find errors, it does not demonstrate their absence. Therefore, we should think about as many situations we can that can make the program fail.

blog 3


As using the subversion for nearly two months, I developed some basic knowledge source control. Source control system consists of some repositories and a number of clients. There are many functions that can be implemented using source control system; for example, this system enforces its own user authentication which allows the source control system to maintain updates to each file, specifically, taping the command diffs, for differences. Storing only the differences, the source control system can keep track of all changes. When you want to see a complete copy of your file, the system performs a merge of the differences, actually, these differences are kept in separate files until you merge your updates, and then you can perform a commit action. We use this approach very often in order that my partner and I are in the step. Thus, this approach allows me and my partner to work in parallel, simultaneously writing code for multiple shared projects, without the danger of an individual's code changes overwriting another's. So source control systems can protect you from code conflicts and loss of early sources. In addition, you can store related file in your source control system project. When you pull a project, or check out the project file; the newer version of the project file overwrites the older version without merging. You might share your project file among all the developers on your team, and when you check a project file into a source control system repository, the source control system overwrites older versions of the file with the newer one without attempting to merge changes.
However, there are still disadvantages to use subversion. I remember when we were doing the iteration 1; we have to move the file in "lab" directory to a new directory "project". I just copied the whole document to the new directory, then I am not able to turn in my work since there are many hidden svn file in the document, I have to delete them one by one. It took me about two hours to turn in that homework, it is nearly the same time that I wrote the code. After that, when turn in the iteration 2, I have to make sure just copy the file to a new directory, thus get rid of the hidden svn files.
In conclusion, source control has provided numbers of useful functions that can allows multiple developers to work on the same code base in a controlled manner; keeps a record of the changes made over time. In addition, allows you to support multiple releases of your software.

Blog 2


Before going to college, I didn't have much experience working in team. Since all my work is asked to be done individually in high school. My concept of working together is blurring. Actually, I have to say I have no idea how to work in team on one project. However, after two years in college, I have learned a lot from working in teams. The benefits of working in teams seem obvious, but the challenges are still inevitable.
I will share some experience in working together with my partner in programming. Two years ago, I had my first computer science course 1901, and it was also my first time to work in pairs with programming. My partner has a lot programming experience, although we are supposed to work together, actually, I didn't get a lot chances to program. But at that time, I am not really care about if I can do programming or not, I just wanted to finish the lab, get the problems done. After the lab, I spend a lot of time reading the code wrote by my partner. However, it is very difficult for me to understand. I want to ask him what's going on, but for most of time, I didn't know how to describe my question. In addition, because of we are in two different levels, I can't understand his explanations. I think my situation is different from most of students, but it is the truth. I have different partners in 1902 and 2021, but I have to say, I didn't make much contribution in team working. Most of the time, I tried to understand the code written by my partner and learned more or less. As for the course 3081, I started to learn more from working in teams, my partner and I discussed the problem together and tried to understand it together. We keep almost the same pace and we understand each other. I think we work better together because we communicate better. We know we are on the same track and it is much more efficient. Since there are still many labs and projects in front of us, it will be a good chance for us to work together and learn more from working in teams. In opinion, I think we should keep communication a lot, expressing everyone's thoughts. Whenever someone get a question, say it directly, don't be shy and shameful. If you keep silence and stay confused, you will find the problem getting more and more confusing as your work continues.

Blog 1

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After taking several computer science courses in the past, I am excited to learn this course, since it includes lot information in programming, and have a good summary about every programming process. I am sure that I will learn a lot from this course.
Based on the programming experience I have in the past. I think I know more in writing effective comments compared to other areas. Since I was in class 1901, I tried to write all the comments after every function in the program. I think it is the best way to test myself if I have understood every step of the code. Sometimes, we need the comments to come up the code that will implement the aim as well. I will keep writing comments every time as I write the code.
As a student who doesn't have much programming experience, there is really a lot for me to learn in this class. I look forward to improving my skill in some areas such as testing frameworks, writing good tests, and designing a useful class hierarchy. Based on my programming experience, I believe that the test codes are always playing an important role in coding. It is a useful approach to find out the program problem; it can give you clue of where your bug is or what kind of logic mistake you made. Writing good tests is a very efficient way to analysis your program and makes it perfected. Also, designing a useful class hierarchy is crucial as well. As we know that the Abstract Data Types are the foundations of class, they created models of objects for programmer, in order to have a better understanding of the code we wrote. The role of the class hierarchy designer is not only to design the class hierarchy but also to create a rationalization of the class hierarchy. First, the logical conditions identify the way in which the base class is refined by the derived class. In addition, the difference between two peer classes can be understood by comparing their logical conditions. For me, I really lack the knowledge of these two aspects which I believe are crucial for a programmer, so I expect to learn more in this class and do more practice.

Recent Comments

  • tongx114: I also think testing is one of the most important read more
  • mueh0096: Agreed. I also found that our introduction to cxxTest was read more
  • zhan1378: Yes, thinking about testing is quite important. And i think read more
  • busa0017: It is easy to write code that covers most cases read more
  • liux0587: Hi, I like the way you introduce the concept of read more
  • borkx026: I appreciate your explanation for unit testing and why it read more
  • tongx114: I am strongly agree with you. The hidden ".svn" file read more
  • liux0587: Hi, I had similar trouble with copying files to directories read more
  • zhan1378: The hidden files and folders really annoyed me when i read more
  • norhe003: I experience something similar to what you describe in this read more

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