What are the best practices for copy constructors in C++?

What are the best practices for copy constructors in C++?

When implementing copy constructors in C++, you should follow these best practices: 1. Use the copy-and-swap idiom for exception safety. 2. Ensure deep copies for dynamically allocated resources. 3. Handle self-assignment gracefully. 4. Mark the copy constructor as explicit if it takes a single argument.

Can you explain the copy-and-swap idiom?

Sure! The copy-and-swap idiom involves creating a copy of the object and then swapping it with the current object. This ensures that resources are managed correctly and provides strong exception safety.

What should I do in case of self-assignment?

In the copy constructor, you can check for self-assignment by comparing the address of the current object with the address of the source object. If they are the same, you can simply return without making any changes.

Are there any common mistakes to avoid?

Yes, common mistakes include forgetting to handle dynamic memory properly, not implementing the copy constructor when needed, and failing to mark the copy constructor as explicit when appropriate.