Twelve rules for naming variables

General rules

Rule one

Intuitively, you can spell , Look at the text and know the meaning , Easy to remember , Use English words or combinations , Pinyin is not recommended , English words should not be too complicated , It is recommended to use the abbreviation

  Rule 2

The variable length conforms to “min_length && max_information”, such as Max_value Replace maxvalueuntiloverflow, Longer words can be abbreviated by removing vowels  

Rule three

When the identifier consists of more than one word , The first letter of each word should be capitalized , The rest are in lowercase

for example int CurrentVal;         // It looks clear and understandable

Rule 4

Try to avoid numbers in names , For example, I used to like to use value1,value2,value3 wait , Unless it is logically necessary , Like driver development and pins , Numbering is easier to use

Rule five

Global variables or functions that are commonly used among multiple files must be marked with a range limiting symbol ,（ It is recommended to use the module abbreviation as the scope qualifier ）

 

Rule 6

Symbol naming has two parts , Specification identifier prefix （ suffix ）+ Meaning identification , Global variables to g or g+ Module abbreviation ( Capitalization ) Prefix , Variable names followed by the first capital letter .C The global variable in is an unstable factor , Be alert , Use prefix to explicitly identify variables as global , It can prompt . Add the abbreviation of the module before the name , When integrating and linking multiple modules , Avoid duplicate names of global variables between modules .
In local variable , Cycle count / Array subscripts are available i,j,k,m Sequential representation . in addition to , Prefix other variables to indicate variable type , There is no unified specification for prefixes ,p For the pointer ,pf Pointer to function ,f Single precision floating point ,db Double precision floating point ,u,s Represents unsigned and signed numbers respectively , namely unsigned And signed. In this way, its type can be seen from the variable name , And avoid some bug

Templates ： Module name abbreviation _ Scope prefix | Data type prefix |【 Pointer prefix 】| Meaning identification | Array / Structure suffix

Rule seven

Scope prefix naming rules

Identifier type	Scope prefix
Global variables	g
File local variables	n
Function local variable	f
Local scope variables	a
Global function	g
Static functions	n

Rule eight

Data type prefix naming rules

Prefix	suffix	data type	remarks
bt		bit
boolean		boolean
char		char
i		int
s		shrot[int]
l		long[int]
u		unsigned[int]
d		duoble
f		float
p		pointer	Pointer prefix
v		void
st		enum
st		struct
st		union
fp		function point
	_a	array of
	_st	typedef enum/struct/union

Rule nine

The meaning of the variable consists of the identifier ： The target word + Verb （ past participle ）+ adverbial + The goal is

for example ：DataDeletedFromSD

Function meaning and identifier constitute ：

Verb （ Present tense ）+ The target word + adverbial + The goal is

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Rule 10

All macro definitions , Enumeration constant , Read only variables are all named in capital letters , Divide words with underscores .

for example

const int MAX_LENGTH = 100;

#define FILE_PATH “/usr/tmp”

Rule 11

Don't forget to initialize when defining variables . The compiler does not necessarily empty this memory when defining variables , Its value may be invalid data .

Rule 12

Considering habit , Local variables can be named in a common way , Is limited to n,i,j Etc. are used as loop variables .

2022 year 7 month 5 Japan 21:26:07  Administration building