What’s the difference between a class and a struct?
Swift version: 5.2
Classes and structures (structs) are so similar in Swift that it's easy to get them confused at first, but actually there are some important underlying differences:
- A struct cannot inherit from another kind of struct, whereas classes can build on other classes.
- You can change the type of an object at runtime using typecasting. Structs cannot have inheritance, so have only one type.
- If you point two variables at the same struct, they have their own independent copy of the data. With objects, they both point at the same variable.
That last point is particularly important: with a struct you know your data is fixed in place, like an integer or other value. This means if you pass your struct into a function, you know it's not going to get modified.
SPONSORED Are you tired of wasting time debugging your Swift app? Instabug’s SDK is here to help you minimize debugging time by providing you with complete device details, network logs, and reproduction steps with every bug report. All data is attached automatically, and it only takes a line of code to setup. Start your free trial now and get 3 months off exclusively for the Hacking with Swift Community.
Sponsor Hacking with Swift and reach the world's largest Swift community!
Available from iOS 7.0
Similar solutions…
- SwiftUI tips and tricks
- How to create live playgrounds in Xcode
- How to create a random terrain tile map using SKTileMapNode and GKPerlinNoiseSource
- How to use Instruments to profile your SwiftUI code and identify slow layouts
- How to localize your iOS app
About the Swift Knowledge Base
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.
