C++ Naming Conventions

Definitions

Types of 'Casings'

Names and examples of named case-types.

Pascal Case (Studly Caps)

NumberOfWords = 3
MyGreetingText = "Hello World"

Camel Case

numberOfWords = 3
myGreetingText = "Hello World"

Upper Snake Case

NUMBER_OF_WORDS = 3
MY_GREETING_TEXT = "Hello World"

Lower Snake Case

number_of_words = 3
my_greeting_text = "Hello World"

Kebab cases

number-of-words = 3
my-greeting-text = "Hello World"

Naming Convention

This section is far from complete, but the basics are there at least.

General

• Types are always declared in a namespace (to prevent naming collisions).
• Each class has its own header and code file if possible.

Files

Header files (.h)

Header files are clean and contain functions and class declarations having documentation blocks (Doxygen) and do not contain definitions to keep them clean and easy to read.
A distinction is made between inline and non-inline definitions.

Definition files (.hpp)

Contains the definitions of template functions or class methods and inlined functions or class methods declared in the header file.

Definition files (.cpp)

Contain the definitions of the functions and class methods declared in the header files.

Namespaces

• A namespace name is an abbreviation or mnemonic in all lowercase.

Functions

• Names are in "Camel Case".
• The first word is a verb in the lowercase followed by one or more nouns.

Classes & Structs

• The file is named after the class using "Pascal Case".
• The class name is a noun or a combination of nouns in "Pascal Case".
• Arguments passed to function are in "Lower Snake Case".
• Public data members are in "Camel Case".
• Private or protected data members are in "Camel Case" prefixed with an underscore '_'.
• Each method name begins with a verb followed by one or more nouns.
• Methods members are in "Camel Case".
• Method or constructor arguments are in "Lower Snake Case".

Enumerates

• An enumerate type name is a noun or a combination of nouns in "Pascal Case" prefixed with 'E'.
• Values entries of an enumeration are in "Camel Case" prefixed using all capitals of the type in lowercase.
• Anonymous enumerates are used as constants are named using "Upper Snake Case".

Templates

• A template class name is a noun or a combination of nouns in "Pascal Case" prefixed with 'T'.

Defines or Global Constants

• Naming consists of nouns in 'Upper-Snake-Case'.
• Order the nouns in the name in order of importance.

Example

The example is using the Allman code styling of braces which translates to a .clang-format file.

Filename, according to this convention, looks like this ArgumentMultiplier.h and has this fictive class.

#define LENGTH_MAX 200

constexpr int LENGTH_MIN{100}; 
 
// Linux namespace.
namespace lnx
{

class ArgumentMultiplier
{
  public:
    ArgumentMultiplier(int argument_one, int argument_two);

    [[nodiscard]] int getResult() const
    {
      return _argumentOne * _argumentTwo;
    };

    enum EResultType: int
    {
      rtNegative = -1,
      rtZero = 0,
      rtPositive = 1,
    };

    EResultType resultType{rtZero};
  
  private:
    int _argumentOne{0};

    int _argumentTwo{0};
};
 
}

AI Rules as Context for Generating Code

The following should be copied when asking for code C++ generation by an AI to get the correct formatted code.

Apply the following instructions on generating the C++ code:
 
- Use only up to C++17.
- Enforcing Allman bracing.
- Doxygen-style comments in headers only.
- Use `#pragma once` as header sentries.
- Use tabs for indentation.
- Use tabs size is 2 characters.
- Use no open lines in function bodies.
- Comments in code are always placed above the code line and never behind it.
- Comments must be full sentences ending with a period.
- Comments must be placed above the code line they describe, never trailing on the same line.
- Camel-case naming is used for object methods.
- Camel-case naming is used for object data-members and starts with an underscore.
- Lower-snake-case is used for class method and function argument names and also for the variables declared in them.
- Const expression and define names are in Upper-Case-Snake.
- Pascal Case is used for naming classes and structures.
- Pascal Case is used for naming enumerate types and prefixed with the letter 'E'.