Important Notes

• Move semantics transfer ownership instead of copying; use std::move to enable efficient resource reuse.

• Rvalue references (T&&) bind to temporaries, enabling move constructors and move assignments.

• std::unique_ptr provides exclusive ownership—cannot be copied, only moved.

• std::shared_ptr enables shared ownership—resource deleted when the last owner is destroyed.

• std::weak_ptr observes a shared_ptr without extending its lifetime; use lock() to check validity.