cpp_style

Useful resources

• https://google.github.io/styleguide/cppguide.html
• http://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines
• many others ...

General naming policies

Filenames with ordering numbers

• Start numbering with 0.

• Pad numbers with zeros: 001, not 1.

• Always increment numbers to avoid naming collisions in repositry history. For example, if there are two tests test_005 and test_010 in a certain module, a newly added test must have name test_011 and not test_000 nor test_006.

Dates

• Dates must always be specified in YYYY-MM-DD order to be sorting-friendly, e.g., 2018_10_02, various delimiters can be used depending on the context.

• Pad months and days with zeros.

General formatting policies

• Use auto-formatting utilities when possible.

• Configure your text/source editor to drop trailing whitespaces. Lines with different number of trailing whitespaces are generally treated as different by various diff utilities.

• Use tabulations only when necessary, e.g, in makefiles.

• Formatting of human-readable files should never favor horizontal or vertical space preservation over readability: separate logical blocks with multiple empty lines and/or comments, add extra linebreaks and whitespaces, etc.

C++ coding style

General rules

Tabulation

• No tabs should be used. Indentation must include 4 spaces.

Naming

• Function names, variable names, and filenames should be descriptive; avoid abbreviation. Types and variables should be nouns, while functions should be "command" verbs.

• Prefixes are usually more apparent than suffixes, so the former is preffered in special names, e.g., g_global_variable instead of global_variable_g.

Other

• Minimize scope of entities -- minimal exposition does not distract with non-essential details and provides minimal base for potentially dangerous assumptions regarding implementation.

• Be explicit in order to minimize the effort required to understand your code, e.g., do not use auto type and using for namespaces, never use unnamed values.

Specific rules

Files

• Filenames should be all lowercase and may include underscores _.

• Extensions of C++ source and header files should be .cpp and .h respectively.

Type names

Names of all types -- classes, structs, typedefs, and enums -- have the same naming convention:

• Type names start with a capital letter and have a capital letter for each new word, with no underscores: MyExcitingClass, MyExcitingEnum.

Enumerations

• All enumerations must be defined within some container class scope.
• Names of the enumerators should be in upper case with underscores.

Variables

• Variable names are all lowercase, with underscores between words, i.e., my_table_name.

• Global variables must be avoided. If it is not possible, their names must have g_ prefix, e.g., g_my_global_variable.

Functions and methods

• Functions should start with a lowercase letter and have a capital letter for each new word without underscores.

• Function names should typically be imperative, i.e., they should be commands: openFile().

• Parameters, which do not serve as outputs, must be marked with const.

• Output parameters must be gathered in the beginning of the list of parameters: doSomething(output1, output2, input1, input2 = <default_value>).

Classes

• It is not allowed to mix definitions with different access modifiers, i.e., methods and members with the same access modifier should be gathered together.

• It is recommended to use access modifiers multiple times to visually separate members from methods.

• Names of member variables should have trailing underscores, i.e., member_name_.

• Methods, which do not change the corresponding class, must always be marked with const.

• In general, destructors of base classes must be defined and must be protected. If it is necessary to allow polymorphic destruction, the destructor should be defined as public and virtual.

• Constructors of base classes should be protected as well.

Macro

• Macro should be avoided when possible.
• Macro name must be in all capitals with underscores.

Namespaces

• Names of namespaces should be in lower case with possible underscores.

Templates

• Names of template parameters should follow the same conventions as the category they belong to (typenames, variables), but their names must include t_ prefix: t_BaseClass.