Struct and class: The main differences in Swift

Struct and class are key components in most iOS applications. They help us organize and manage code into blocks in an intuitive and easy-to-use way. So coming to this blog, we will clarify the main differences between struct and class in Swift and also learn more when we use them for proper collaboration.. Let’s go

What is struct and class?

Struct is a value type which allows your to change other instance if you change one instance, that contain:

  • protocol conformances
  • extensions
  • properties
  • methods
  • subscripts
  • initializers

Class is a reference type which doesn’t allow you to change another instance if you change one instance. It includes:

  • subscripts
  • initializers
  • protocol conformances
  • extensions
  • properties
  • methods

What are the differences between struct and class?

Generally, struct and class are pretty similar. However, there’s still lots of differences between them you need to know 

Value vs reference types

One of the most distinctions is the type. As mentioned above, struct is a value type, meanwhile, class is a reference type. 

Reference of class indicates that each instance shares the data when you copy reference type. As a result, The reference itself is copied instead of its data references. In addition, whenever you change one, the other may change.

Value of struct, each instance maintains a unique copy of the data. In case you change one instance, the other still keeps .

The benefit of mutation in safety

In case of having mutation, struct is better than class in mutation protection. Because no other part of your app is modifying the data at the same time. As a result, this makes it easier to reason about your code, which is particularly useful in multi-threaded environments where several threads can be modifying your data at the same time.

Besides that, ii it does not have any mutation appearance, the benefit of mutation also does not count. Therefore, structs act exactly the same as classes. 

Structs and constants

Struct was defined as a variable instead of the way we did with Class. There is a mutation if a struct defines as a variable.. Let’s see the following example:

Struct vs class

Structs get an initializer for free

The Class receives a defined initializer. On the other hand. Struct will get a free initializer 

 class and struct

Classes allow inheritance

Classes can inherit characteristics from other classes and thus act as abstract classes. This is often no longer required and can be replaced with protocols in Swift. Inheritance is only available with classes, whereas protocols can use both classes and structs.

Classes are ability to be deinitialized.

A deinit method on a class allows it to execute code just before it is destroyed.

When Should You Use Struct and Class?


  • Using for simple data types
  • Choosing struct instead of class in a multi-threaded environment
  • Using structs within class types
  • Because Structs can’t inherit code from other structs, there are a few options for creating flexible code.


  • Using class for creating a subclass of UIViewController
  • Because of deinitialization of classes,you have permission to make one or more references to the same class
  • Comparing instance identity is needed by using ===


Hopefully, you got our helpful above information about The main differences between struct vs class in Swift. In case you find some difficulty in Mobile application Development, let ArrowHitech team help you.

 Visit us to find out helpful information