201621123031 Java Programming 5th Week of study summary

1. Study summary of this week 1.1 write down the key points of knowledge that you think are important in your study this week

Keywords: interface, polymorphism, Comparable,comparator

1.21.2 try to organize these keywords using mind mapping. Note: Mind mapping generally does not need to appear too many words.

2 written assignments 1. Object-oriented design (team project, 2-3 people)

Content: Continue to improve the last big job.
Note: After a few more classes to talk about Java Graphics interface programming, the time to upgrade the system to a graphical interface. The part of the business logic of the system should not change much, the change is the part of the input and output. When encoding, do not bind the code that handles input (system.in) and output (System.out) to a business processing method.

2.1 System common function frame diagram

2.2 System General Class diagram

2.3: Shopping cart, commodity, System key code (mainly to intercept own responsible parts)

2.4 Other: Compared with the previous system, the design of the system and other changes. Other impressions.

Due to lack of knowledge, there are many defects

3.abstract: Reading Guessgame abstract class design and use source code 3.1 guess the pre-transformation code is very simple, and the modified code uses abstract classes, abstract methods, it seems more complex, what is the benefit of such a transformation?

You can run the word-guessing game directly before the makeover,
After that, define a variable and call go.

3.2 Guessgame (after transformation). There are abstract and non-abstract methods in Java, and you think that what methods in the abstract class should be declared abstract, and what methods do not need to be declared as abstract directly implemented.

1,abstract modifies the class to make this class an abstract class that will not generate an object instance, but can be used as a type of object variable declaration, that is, a compile-time type, an abstract class that, like a class of semi-finished products, requires subclasses to inherit and overwrite the abstract methods.
The 2,abstract modification method makes this method an abstract method, that is, only the declaration (definition) is not implemented, and the implementation part is replaced with ";". Subclass inheritance Implementation (overwrite) is required.
Note: Classes with abstract methods must be abstract classes. But abstract classes are not necessarily abstract methods, but they can all be concrete methods.

3.3 In this example, what is the change, and what is the constant? Try to describe it in conjunction with concepts such as abstract.

The constant is the function, the change is the realization method.

4 count the amount of code completed this week

Week number	Number of rows	number of new rows
1	\57	57
2	200	400
3		508
5	350	350

201621123031 Java Programming 5th Week of study summary