Why does an object in Swift not free memory immediately after deinitialization?

In Swift, an object does not immediately release memory after the deinitializer (deinit) is called because memory management is handled by the reference counting system (ARC — Automatic Reference Counting).

deinit is called when the reference count of the object reaches zero, meaning there are no more strong references to the object. However, the actual memory release can occur later because:

• ARC may optimize memory release.
• If the object is involved in cyclic references, deinit may not be called at all until the cycles are broken.
• In some cases, the system may delay memory release to optimize performance.

Thus, deinit is a signal that the object is ready to be removed, but the actual memory release is managed by ARC and the memory management system.