#memory-management

Explain the concept of "ownership" in Rust. What are the three main rules of ownership? How does it help Rust achieve memory safety without a garbage collector? Provide a simple code example that would cause a compile-time ownership error and explain why it fails.

Explain the difference between `std::unique_ptr`, `std::shared_ptr`, and `std::weak_ptr` in modern C++. When should each one be used? Provide a code example demonstrating a common use case for `std::shared_ptr` to manage a shared resource.