20182301 2019-2020-1 "Object-oriented programming and data structures" Experimental Report 3

Course: "Programming and Data Structures"
Class: 1823
Name: Zhao Pei Ning
Student ID: 20182301
experiments Teacher: Johnny
experiment Date: September 23, 2019
Compulsory / Elective: Compulsory

1. Experimental content

Download and install and use the IDEA, following the completion of the experiment ( https://www.cnblogs.com/rocedu/p/6371315.html ).

Initial grasp of unit testing and TDD
Understand and master the object-oriented three elements: (! Own to learn) encapsulation, inheritance, polymorphism
Preliminary master UML modeling
On completion of the cloud blue ink (1) - (5) experiments.

2. Experimental procedure and results

First

Writing Product code MyUtil.java
Writing test code MyUtilTest.java
1. project -> (right) new -> Directory
2. test ——>(右键) make directory as ——> Test Source Root
TDD use
1. File ——>settings ——>plugins ——>junit
2. Small bulbs creat test
3. File ——>Project Strsture
testing successfully

the second

Manual play StringBuffer, several methods should experiment with them, and to distinguish the differences between StringBuilder, StringBuffer, String class
The method of learning equals, modify the error code (tupianequals on page :)
Writing the test code according to the above method
testing successfully

The third

SOLID principles of learning

the fourth

In UML good design, ease of code smoothly
Constructor initializes the data
The use of two numbers encapsulated getX
Product code writing and testing code
testing successfully

3. Experimental problems encountered in the process and settlement process

Question 1: StringBuffer methods do not expand capacity in space (the blog screenshots wrong, believe in yourself)

Problem 1 Solution :( teacher thinking questions made me understand its use)

  public static void main(String[] args) {
StringBuffer sb = new StringBuffer("cccccccccccc");
System.out.println("sb:" + sb);
System.out.println("sb.capacity():" + sb.capacity());
System.out.println("sb.length():" + sb.length());

StringBuffer sBuffer =new StringBuffer();
sBuffer.append("cccccccccccc");//12个c
System.out.println("SBuffer's capacity"+sBuffer.capacity());

}
}

Why the different results?
Both methods are not the same store, the last space storage methods are not the same.

Problems 2: java prepared complex class code arithmetic multiplication, division problems

Problem 2 Solution: a complex class of simple addition and subtraction, multiplication and division to think about: not just use two variables is solved, require multiple auxiliary variables.

Other (perception, thinking, etc.)

The code is now gradually increase the difficulty, if not seriously study and understand thoroughly, it is prone unable to write phenomenon. I should actively take the initiative to learn, to root out some knowledge, and finally succeed. On the blog may be wrong, there is evidence in the case, I believe in yourself!