swift struct와 class의 차이를 알려줘

In Swift, the primary difference between structs and classes lies in their semantics and memory management:

1. Value Semantics vs. Reference Semantics:

   • Structs: These are value types, meaning that when you assign a struct to a new variable or pass it to a function, a copy of the data is made. This ensures that changes to one instance do not affect another. This behavior is demonstrated in the session A Swift Tour: Explore Swift’s features and design.
   • Classes: These are reference types, which means that when you assign a class instance to a new variable or pass it to a function, you are passing a reference to the same instance. Changes to one reference will affect all references to that instance. This is explained in the session A Swift Tour: Explore Swift’s features and design.

2. Memory Management:

   • Structs: Swift automatically manages memory for structs, and they are stored inline wherever they are used.
   • Classes: Swift uses Automatic Reference Counting (ARC) to manage memory for class instances. This involves keeping track of the number of references to a class instance and deallocating it when there are no more references. However, this can lead to issues like retain cycles, which need to be managed using weak references.

3. Inheritance:

   • Structs: Do not support inheritance. They are typically used for simple data structures.
   • Classes: Support single inheritance, allowing you to create a class hierarchy.

4. Use Cases:

   • Structs: Best used when you need a simple data structure that benefits from value semantics, such as when you want to ensure that data is not shared unintentionally.
   • Classes: Suitable for more complex data structures that require shared mutable state or identity.

These differences are crucial for understanding how to effectively use Swift's type system to write efficient and safe code.