Atitit in-depth understanding of the nature of software Attilax summary software Three principles "three times principle" is dry principle and yagni principle of the fold

atitit in-depth understanding of software essence attilax summarize software three principles "three times principle" is the dry principle and the Yagni principle

1.1.1. nature of software: Abstraction 1

1.2. The process of software development is the process of Continuous Abstraction 1) machine language------assembly language---- high-level languages, which is a process of continuous abstraction,1

1.3. Code Abstract Three Principles _ Software Engineering _ Cool net . htm1

1.4. " software is a compact combination of storage, communications,UI(user Interface), and business logic 2

1.5. in the software life cycle, the more stable is the storage and the communication, the most changeable is the business logic;2

1.6. at the software level, storage and communications are generally at the bottom, while business logic is at the top 2

1.7. How is abstraction of software abstracted?? Level of abstraction no more than three layers 2

1.8. What is abstract?? that is, it is possible to draw it out as the first layer of abstraction 2

1.1.1. The nature of software: Abstraction

1.1. The process of software development is the process of continuous abstraction. 1) machine language ---------------------a process of continuous abstraction

with the improvement of the level, people's development efficiency is more and more high. function /process is an important abstraction

A file is also a level of abstraction

A package in the Java language, a C # namespace that belongs to a higher level of pumping at this level

The module division of software Architecture is the abstraction of system

1.2. Code of the abstract three principles _ Software Engineering _ Cool network . htm

First, Dry Principles

Second, YAGNI Principles

YAGNI is the acronym for you aren ' t gonna need it , meaning " you won't need it ".

Third, Rule of three principle

Rule of three called the " three-times principle ", refers to the " abstraction "of a function when it appears for the third time.

Second, Three common abstract methods classify class, gather aggrate

category class students (Wang Lan, Li Wei)

aggregates The relationships of Aggrate objects with attributes. (Li Wei, name, age)

summarizing generation students, undergraduates, postgraduates

1.3. " software is a tight combination of storage, communications,UI(user Interface) and business logic

1.4. in the software life cycle, the more stable is the storage and the communication, the most changeable is the business logic;

1.5. at the level of software, storage and communications are generally at the bottom, while business logic is at the top1.6. How is abstraction of software abstracted?? The level of abstraction does not exceed three layers1.7. The higher the level of abstraction, the more ambiguous the semantics of the interface, the wider the scope of application, and the final mathematical model or concept:1.8. What is abstract?? that is, it is possible to draw it out as the first layer of abstraction.

Is the first abstraction to draw a horse?

In the abstract is an animal, animals, there is no way to speak out. In the upper layer, the creature, the root adds no way.

1.9. Abstract Hierarchical concrete vs abstract

when you say "This is a cat", if you stand on a mammal's point of view this sentence is specific, and if you stand in the Persian cat point of view this sentence is abstract. It can be seen that the same paragraph is specific at a higher level of abstraction than it is abstract at below its level of abstraction. All things, such as creature----------------animal---------------------

Resources

Software Abstraction -Tony Bai- blog bus . htm

data abstraction and three kinds of abstract methods _ Baidu Library . htm

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Atitit in-depth understanding of the nature of software Attilax summary software Three principles "three times principle" is dry principle and yagni principle of the fold