Critical Patterns

Smart Pointers (REQUIRED)

// ✅ ALWAYS: Use smart pointers auto user = std::make_unique<User>("John"); auto shared = std::make_shared<Config>();

// ❌ NEVER: Raw new/delete User* user = new User("John"); delete user;

RAII (REQUIRED)

// ✅ ALWAYS: Resource management through constructors/destructors class FileHandle { std::fstream file_; public: FileHandle(const std::string& path) : file_(path) {} ~FileHandle() { if (file_.is_open()) file_.close(); } };

Modern Patterns (REQUIRED)

// ✅ Use auto for type deduction auto items = std::vector<int>{1, 2, 3};

// ✅ Use range-based for loops for (const auto& item : items) { process(item); }

// ✅ Use structured bindings auto [name, age] = getPerson();

Decision Tree

Need unique ownership? → std::unique_ptr Need shared ownership? → std::shared_ptr Need optional value? → std::optional Need multiple types? → std::variant Need string views? → std::string_view

Commands

g++ -std=c++20 -Wall -Wextra main.cpp -o app clang++ -std=c++20 main.cpp -o app cmake -B build && cmake --build build