Swift Inheritance

Swift Inheritance

In Swift, a class can inherit properties and methods from another class, which is known as inheritance. This allows the child class (also known as the subclass) to reuse the functionality of the parent class (also known as the superclass), and to extend or modify that functionality as needed.

Here is an example of how to define a superclass and a subclass in Swift:

class Vehicle {
    var numberOfWheels: Int
    var color: String

    init(numberOfWheels: Int, color: String) {
        self.numberOfWheels = numberOfWheels
        self.color = color
    }

    func startEngine() {
        print("Vroom!")
    }
}

class Bicycle: Vehicle {
    var hasBasket: Bool

    init(numberOfWheels: Int, color: String, hasBasket: Bool) {
        self.hasBasket = hasBasket
        super.init(numberOfWheels: numberOfWheels, color: color)
    }

    override func startEngine() {
        // Bicycles don't have engines, so we'll just print a message instead
        print("Pedaling along...")
    }
}

In this example, the Vehicle class is the superclass, and the Bicycle class is the subclass. The Bicycle class inherits the numberOfWheels and color properties, as well as the startEngine() method from the Vehicle class. It also adds its own hasBasket property and overrides the startEngine() method to provide its own implementation.

You can then create instances of the Bicycle class and use them like this:

let myBike = Bicycle(numberOfWheels: 2, color: "red", hasBasket: true)
myBike.startEngine()  // Output: "Pedaling along..."

In this code, the myBike variable is an instance of the Bicycle class, which inherits the properties and methods of the Vehicle class and provides its own implementation of the startEngine() method. When you call the startEngine() method on the myBike instance, it uses the implementation provided by the Bicycle class, which prints the message “Pedaling along…”.