20,182,312 2019-2020-1 "data structures and object-oriented programming," the second and third week learning summary

Learning content summary

boolean type: only right and wrong;
Scanner class: import declaration object using the new operator to create;
String class: char charAt (int index) Returns the index of the character at the specified;
Random categories: pseudo-random number generator and performs a complex machine operator to obtain a pseudo random number;
Math class: Math class is a static method, called through the class name;
DecimalFormat: formatted output.

Textbook learning and problem-solving process

Question 1: What is the escape character?
Question 1 solution: escape character is a backslash () at the beginning of a string of characters
Question 2: Scanner role
Problems Solution 2: Scanner class provides a method of reading different types of data from different data sources.

Code debugging and problem solving in the process

Question 1: forget the screenshots.
Problem 1 Solution: next cut.
Question 2: does not display the symbol type in which a string of letters when taken.
Problem 2 Solution: the input is defined as the char type String class.
Question 3: When facing the code book to write, do not go find a digital input.
Question 3 Solution: float and double types of digital input into the time, scan.nextInt should become scan.nextdouble or scan.nextfloat.

Code hosting

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Last week exam wrong question summary

1 title and the wrong reasons, to understand the situation
Which of the following will yield a pseudorandom number in the range [-5, +5) given the following:

= New new Gen the Random the Random ();
A
.
Gen.nextFloat (). 5 *
B
.
Gen.nextFloat () * 10 -. 5
C
.
Gen.nextFloat (). 5 * - 10
D
.
Gen.nextInt () * 10 -. 5
E
.
gen.nextInt (10) - 5 answer: B understood that: any number of -5 to 5 use a random number taken float.

Question 2 and the wrong reasons, to understand the situation
All at The Methods in at The Math class are declared to BE static.
A
.
To true
B
.
False Answer: A comprehension: the book knowledge: Math class methods static.
Problem 3 and the wrong reasons, to understand the situation
If you want to store into the String name the value "George Bush", you would do which statement? ( If you want to "George Bush" this value is stored as a string type name, you ? will execute that statement)
A
.
String name = "George Bush";
B
.
String name = new new String ( "George Bush");
C
.
String name = "George" + "" + "Bush";
D
.
String string = new new name ( "George" + "" + "Bush");
E
.
the Any of Would Work at the above (the above can be done) answer: E understand: naming a string, keep in mind!

Pair peer review and
Worth learning problems or blog:
- Of knowledge on materials summarize very refined
- A description of all the problems are not with screenshots, can not directly reflect the problem, next time remember screenshot
- Textbook understanding of the problems is not enough, and more confined to the surface
Code is worth learning or problem:
- Code is structured, clear thinking, wrong can be very easy to find errors.
- The script does not indicate the number of rows, check the error position to succeed count the number of rows
- Code is a problem related to the ignorant and the point of force
Based on score, I give this blog scoring: 14 points. Scores are as follows:

Proper use Markdown syntax (1 point)
Elements range (1 point) template
Textbook learning and problem solving process, a problem of 2 points plus 1 point
Code debugging and problem solving in the process, a problem of 2 points plus 1 point
Week over 300 branches valid code (plus 2 points)
Other plus points: 6 points
- Feelings, experience does not leave large empty 1 point
- Progress bar records the learning time and improve the situation of 1 point
- There are hands-on writing new code, add 1 point
- Learning the wrong questions in depth, add 1 point
- Comments seriously, I can point out problems and blog code plus 1 point
- Pair learning authentic plus 1 point

Comments had students blog and code

Pair this week learning
- 20182308
- Pair Photo

- 结对学习内容
    - 与结对同学交流学习完成了课后的作业
    - 与结对同学互相帮助通过了实验
    - 与结对同学互相交流了对String类和格式化输出
    - 我同他讲解了封装的思想，我们同时受益匪浅

Last week blog peer assessment case
- 20182308

Other (perception, thinking, etc., optional)

Sentiment: Not only are case sensitive issue, even if it is the number of words in Java characters have to note that when a character must use char type, which I did not expect, this exchange again and again I came to understand the logic of Java mode. Although the input mode and ease of use is, Java seems to be more complex than the c language, but perhaps because of this, it makes me feel something that I was writing a can be used, rather than straight to the logic do a mathematical problem.
Thoughts: Now I still often an error code, it is probably still knock and I usually open book about the code at every turn, not skilled muscle memory that will always leak the leak, the future certainly more than the machine, learn skilled Java.

Learning progress bar

	The number of lines of code (add / accumulate)	Blog amount (add / accumulate)	Learning time (add / accumulate)	Important growth
aims	5000 rows	30	400 hours
the first week	130/130	2/2	20/20	Initially I learned to learn Linux commands and debugging Java code running
the second week	451/581	3/5	20/40	Preliminary learned how to use various output classes and methods
The third week	500/1000	3/7	22/60
the fourth week	300/1300	2/9	30/90

Plan study time: 30 hours
The actual study time: 20 hours
Improvements:

The use of the class of less skilled, the logic of Java is not completely figured out, but quite a lot better than before.

The second and third week learning summary