C++ Coding Standards

When reviewing or generating C++ code, follow these rules:

File Naming

• Source files: snake_case or PascalCase with .cpp extension (e.g., user_service.cpp or UserService.cpp)
• Header files: Same base name with .h, .hpp, or .hxx extension
• Template files: .tpp or .inl for template implementations
• Be consistent within a project

Header Guards / Pragma

• Prefer #pragma once for modern compilers
• Or use traditional guards: UPPER_SNAKE_CASE with _HPP suffix

#pragma once
// or
#ifndef USER_SERVICE_HPP
#define USER_SERVICE_HPP
#endif

Namespace Naming

• Namespaces: all_lowercase or snake_case (e.g., myproject, data_processing)
• Nested namespaces: Use C++17 syntax when possible (e.g., namespace project::utils {})
• Avoid using namespace in headers

Variable Naming

• Local variables: snake_case or camelCase (e.g., user_count or userCount)
• Member variables: Prefix with m_ or suffix with _ (e.g., m_data or data_)
• Static members: Prefix with s_ (e.g., s_instance)
• Constants: UPPER_SNAKE_CASE or kPascalCase (e.g., MAX_SIZE or kMaxSize)
• Global variables: Prefix with g_ (e.g., g_config)

Function/Method Naming

• Free functions: snake_case or camelCase (e.g., calculate_total() or calculateTotal())
• Member functions: camelCase or PascalCase (e.g., getUserId() or GetUserId())
• Getters/Setters: get/set prefix or just property name (e.g., getName() or name())
• Factory functions: Create, Make, or Build prefix (e.g., CreateUser())

Class/Type Naming

• Classes: PascalCase (e.g., UserService, DataProcessor)
• Structs: PascalCase (e.g., Point, Rectangle)
• Interfaces: PascalCase with I prefix optional (e.g., ISerializable or Serializable)
• Template parameters: Single letter or PascalCase (e.g., T, Container, KeyType)
• Enums: PascalCase for type, UPPER_SNAKE_CASE or PascalCase for values
• Type aliases: PascalCase (e.g., using StringList = std::vector<std::string>;)

Smart Pointers

• Use std::unique_ptr for single ownership
• Use std::shared_ptr for shared ownership
• Avoid raw new/delete

Organization

• Include guards / pragma once
• System includes (alphabetical)
• Project includes (alphabetical)
• Forward declarations
• Namespace opening
• Class declarations
• Inline/template implementations