Structs and Classes

Structs and classes are the main building blocks for modelling data in Swift. This lesson covers their similarities, key differences, when to use each, and related concepts like properties, methods, and initialisers.

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Defining Structs and Classes

struct Point {
    var x: Double
    var y: Double
}

class Vehicle {
    var make: String
    var model: String
    var year: Int

    init(make: String, model: String, year: Int) {
        self.make = make
        self.model = model
        self.year = year
    }
}

Creating Instances

// Structs get a free memberwise initialiser
var origin = Point(x: 0, y: 0)

// Classes require an explicit init
let car = Vehicle(make: "Tesla", model: "Model 3", year: 2024)

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Value Types vs Reference Types

This is the most important distinction between structs and classes: