C++ Patterns

This file extends the common patterns with C++ specific content.

Modern C++ (C++17/20/23)

• Prefer modern C++ features over C-style constructs
• Use auto when the type is obvious from context
• Use constexpr for compile-time constants
• Use structured bindings: auto [key, value] = map_entry;

RAII (Resource Acquisition Is Initialization)

Tie resource lifetime to object lifetime — no manual new/delete:

class FileHandle {
public:
    explicit FileHandle(const std::string& path) : file_(std::fopen(path.c_str(), "r")) {}
    ~FileHandle() { if (file_) std::fclose(file_); }
    FileHandle(const FileHandle&) = delete;
    FileHandle& operator=(const FileHandle&) = delete;
private:
    std::FILE* file_;
};

Smart Pointers

• Use std::unique_ptr for exclusive ownership
• Use std::shared_ptr only when shared ownership is truly needed
• Use std::make_unique / std::make_shared over raw new

Rule of Five/Zero

• Rule of Zero: Prefer classes that need no custom destructor, copy/move constructors, or assignments
• Rule of Five: If you define any of destructor/copy-ctor/copy-assign/move-ctor/move-assign, define all five

Value Semantics & Error Handling

• Pass small/trivial types by value, large types by const&
• Return by value (rely on RVO/NRVO)
• Use std::optional for values that may not exist
• Use std::expected (C++23) or result types for expected failures

Memory Safety

• Never use raw new/delete — use smart pointers
• Never use C-style arrays — use std::array or std::vector
• Use std::string over char*
• Use .at() for bounds-checked access when safety matters
• Never use strcpy, strcat, sprintf

Formatting & Static Analysis

clang-format -i <file>
clang-tidy --checks='*' src/*.cpp
cppcheck --enable=all src/

Testing

Use GoogleTest (gtest/gmock) with CMake/CTest:

cmake --build build && ctest --test-dir build --output-on-failure

Always run tests with sanitizers in CI:

cmake -DCMAKE_CXX_FLAGS="-fsanitize=address,undefined" ..

Naming Conventions

• Types/Classes: PascalCase
• Functions/Methods: snake_case or camelCase (follow project convention)
• Constants: kPascalCase or UPPER_SNAKE_CASE
• Namespaces: lowercase

Reference

See agents: cpp-reviewer, cpp-build-resolver for C++ review and build error resolution. See skill: cpp-coding-standards for comprehensive C++ guidelines.