Swift Class vs Struct
Swift Class vs Struct
Choose value semantics (struct) for simple data and reference semantics (class) for shared identity, inheritance, or Objective-C interop.
Key Differences
- Copying: Structs copy on assignment and passing; classes pass references.
- Inheritance: Classes support inheritance; structs do not.
- Identity: Classes have identity semantics; structs compare by value (when Equatable).
Example
struct Point { var x: Int; var y: Int }
class Counter { var value = 0 }
var p1 = Point(x: 1, y: 2), p2 = p1 // copy
p2.x = 9 // p1.x remains 1
let c1 = Counter(), c2 = c1 // same instance
c2.value = 7 // c1.value is 7
