Student ID 2017-2018-2 "Program Design and Data Structure" Week X Learning Summary
Textbook learning content summary
This week, I mainly learned the knowledge of inheritance. Using inheritance can make subclasses use methods in parent classes. The variables in the parent class must use the visibility modifier == "protected" == before they can be used by the subclass. Subclasses can inherit the methods of the superclass. However, subclasses cannot inherit the constructor of the superclass. However, the constructor of the parent class can be invoked by a reserved word reference. When the subclass method and the superclass method have the same name, the method will be rewritten and the subclass method will take precedence. A parent class can be inherited by multiple subclasses, and subclasses can also be the parent classes of other classes. The Object class is the parent class of all subclasses. Interfaces cannot overlap with inheritance. The final modifier ensures that the methods of the parent class will not be overridden in the child class.
Problems and Solving Processes in Teaching Materials Learning
- Question 1: Question about the functionality of the Object class.
- Solution to problem 1: I found the answer later on the Internet. The Object class is the parent class of all classes, which means that all classes can directly call methods without defining them. And when the data type is not determined, you can declare it with Object first.
- Question 2: Regarding the use of the static modifier in inheritance.
- Problem 2 Solution: In the process of URL inheritance, static methods cannot be used for abstract objects, because static methods belong to a certain class and need to be called with the class name. An abstract method modifies a particular method.
Problems and solutions in code debugging
Question 1: This week's homework is not very difficult, so I didn't encounter any problems in the homework, but I encountered a problem in the experiment, that is, the assertEquals() method cannot be used to compare two double data in the test class.
Solution to problem 1: Later, the senior asked me to change it to String type to be able to run normally.
code hosting
Summary of last week's exam mistakes
Wrong question 1
Analysis: This question was not carefully read at the time, because I could not understand it. Now it seems that the answer makes sense. One mistake is that the programmer starts programming at 0, or farther from the index.
Error 2
Analysis: Without him, shaking hands.
wrong question three
Analysis: This is also sloppy, but I still talk about it: data type [ ] array name = new data type [ ].
Pairing and mutual evaluation
Review Template:
- Worth learning or questions from the blog:
- xxx
- xxx
- ...
- Worth learning or problems in the code:
- xxx
- xxx
Others (perception, thinking, etc., optional)
有事忙碌的一周，不过又学到了新知识，还算开心。下星期又是一波学习感觉周日对我来说近似于无。learning progress bar
| Lines of code (added/accumulated) | Blog volume (new/cumulative) | Study time (added/accumulated) | important growth | |
|---|---|---|---|---|
| Target | 5000 lines | 30 articles | 400 hours | |
| the first week | 75/200 | 1/2 | 20/20 | |
| the second week | 338/500 | 1/4 | 18/38 | |
| The third week | 516/1000 | 1/7 | 22/60 | |
| the fourth week | 1296/1300 | 1/4 | 30/90 | |
| fifth week | 615/2839 | 1/5 | 20/110 | |
| Week 6 | 610/3449 | 2/7 | 20/130 | |
| Week 7 | 719/4108 | 1/8 | 30/160 |
Planned study time: 30 hours
Actual study time: 30 hours