autojanet/skills/understand/languages/cpp.md

C++ Language Prompt Snippet

Key Concepts

• Templates: Function, class, and variadic templates for generic compile-time polymorphism
• RAII: Resource Acquisition Is Initialization — tie resource lifetime to object scope
• Smart Pointers: unique_ptr (exclusive), shared_ptr (reference-counted), weak_ptr (non-owning)
• Move Semantics: Rvalue references (&&) and std::move for efficient resource transfer
• Operator Overloading: Define custom behavior for operators on user-defined types
• Virtual Functions and Vtable: Runtime polymorphism through virtual method dispatch tables
• Namespaces: Organize symbols and prevent name collisions across translation units
• Constexpr: Compile-time evaluation of functions and variables for zero-runtime-cost computation
• Lambda Expressions: Anonymous functions with capture lists for closures
• STL Containers and Algorithms: Standard containers (vector, map, set) and generic algorithms
• Concepts (C++20): Named constraints on template parameters replacing SFINAE patterns

Import Patterns

• #include <system_header> — include standard library or system headers
• #include "local_header.h" — include project-local header files
• using namespace std — bring all names from std into scope (avoid in headers)
• using std::vector — selectively bring specific names into scope

File Patterns

• .h / .hpp — header files containing declarations, templates, and inline definitions
• .cpp / .cc — implementation files with function definitions and static data
• CMakeLists.txt — CMake build system configuration
• Makefile — Make-based build rules and targets
• main.cpp — program entry point containing int main()

Common Frameworks

• Qt — Cross-platform application framework with signal/slot mechanism
• Boost — Extensive collection of peer-reviewed portable libraries
• Catch2 — Header-only testing framework with BDD-style syntax
• Google Test — Testing framework with fixtures, assertions, and mocking
• gRPC — High-performance RPC framework for service communication

Example Language Notes

Uses std::unique_ptr<T> for RAII-based ownership, ensuring deterministic cleanup when scope exits. The unique pointer cannot be copied, only moved, making ownership transfer explicit and preventing accidental double-free errors.

Header/implementation separation (.h/.cpp) controls compilation boundaries — changes to a .cpp file only recompile that translation unit, not all includers.