Catalog

Chapter six | Coding standards

【 Coding standards 】

【 Software programming efficiency 】

【 unit testing 】

【 Unit test questions 】

choice question

Judgment questions

Short answer

Chapter six | Coding standards

【 Coding standards 】

Basic overview

• Software programming is a complex and iterative process , It's not just about writing code , It should also include code reviews 、 unit testing 、 Code optimization 、 A series of work such as integration debugging .

• Software coding specifications are language specific , A set of rules that describe how to write code .

• reality ： Software life cycle 70% The cost is maintenance . Software is rarely maintained by original writers in its life cycle

• Purpose ： Improve coding quality , Avoid unnecessary program errors . Enhance the readability of the program 、 Reusability and portability

• Good notes explain why , Not how : Do not repeat the description of the code in comments

• When commenting, you need to think about what to write in the comment , Instead of scribbling

• After writing the comments, review them in the context of the code , Do they contain the correct information

• When modifying code , Maintain all comments around the code

【 Software programming efficiency 】

Code optimization

• Optimization is equivalent transformation of code , Make the code running result after transformation the same as that before transformation , But faster execution or less storage overhead .

• according to 80/20 principle , Realize the refactoring of the program 、 Optimize 、 Extensions and document related things usually cost 80% The amount of work .

• Focus on improving overall efficiency 、 Supplemented by local efficiency

• When optimizing the program , We should first find the bottleneck that limits efficiency

• First optimize the data structure and Algorithm 、 Then optimize the execution code

• T(n) and S(n) It is often opposite , Trade offs are needed . Optimize , It is a multi-objective optimal decision , When it is impossible to optimize all goals , Compromise is needed to achieve the overall optimization .

• Correct code is more important than fast code , No optimization can destroy the correctness of the code

• Never try to optimize your code without performing a pre - and post performance evaluation

【 unit testing 】

• Test pass rate refers to the proportion of test cases that pass the test process , Unit testing usually requires the passing rate of test cases to reach 100%.

• Test coverage is a measure of test integrity , You can know whether the test is sufficient and where the weakness is . Code coverage is a measure of unit testing , But also We cannot blindly pursue coverage .

• Coverage criteria ： Statement override 、 Determine coverage 、 conditional 、 Determine conditional coverage 、 Conditional combination covering 、 Path coverage

【 Unit test questions 】

choice question

Judgment questions

Don't fix bad programs , To rewrite . T

Short answer