It’s essential to note here that the Castle class does not have a hasGarage property, and Villa does not have a towers property.īack to type casting. As a result, they both have a property windows in addition to their own properties hasGarage and towers. It adds a property towers, and has a simple initializer.īoth Villa and Castle subclass House. The third class Castle also inherits House. It makes sense: a villa is a house, just like a dirtbike and a car are both vehicles, subsequently inheriting the property wheels and function drive(). The subclass : superclass syntax, such as Villa: House, indicates that Villa subclasses House, and thereby inherits the properties and functions of House. It also adds a hasGarage property, of a boolean type, that indicates whether this villa has a garage for a car. The second class Villa subclasses House, thereby inheriting its windows property. The first class House has one property windows of type Int and a simple initializer. The underlying object doesn’t change, merely the type you use to describe that object. With type casting you treat an object as one of another type. See that bit of text, Tinker Tailor Soldier Spy? That’s human-readable text for us developers, but for Swift it’s just another way to represent data. The type of riddle is explicitly provided with a type annotation, i.e. On the second line the value of riddle is printed out. In the above code you define a constant named riddle of type String, and you assign it the string literal “Tinker Tailor Soldier Spy”. Let riddle:String = “Tinker Tailor Soldier Spy” Here’s an example of a variable with an explicit type annotation: That’s pretty rigid and often leads to verbose code, so the Swift programming language has features like type casting, type inference, protocols, Any and AnyObject, opaque types and generics to create concise, flexible and reusable code. That means that every variable needs a type, and once you’ve given a variable in your code a particular type, it cannot be changed. The Swift programming language is strong-typed. The Swift compiler doesn’t care much about a type, beyond the data it represents! It simply reads our code and translates it to 1’s and 0’s a computer can understand. We use types to represent different kinds of data. Types in a programming language are there for us, the developers. UIButton is used for a button user interface element.String is used for text, like “Tinker Tailor Soldier Spy”.Double is used for decimal-point values, like 3.1415. Int is used for integer values, or “whole numbers”.The Swift programming language uses types, like classes and structs, to represent different kinds of data in your app’s code. Type Casting in Practical iOS Developmentįirst things first.Stream music, and reach out to a wider audience with the help of your own radio app.Ĭonnect with your congregation instantly by creating an app for your church.Ĭreate an online dating app and let your app users find the perfect match with just a swipe.Ĭreate a taxi booking app and let your users book a cab in real-time, track the ride, and reach their destination. Let your customers conveniently shop, buy, and browse your stores with a shopping mobile app. Turn leads into clients and prospects into sales with the help of a mobile app for your business. Let customers reserve tables, pay bills, & find your restaurant through a restaurant mobile app. Learn how to make an app in easy steps with our no-code app maker and how to publish it to app stores.Ĭreate an app for users to order goods & receive it with live package tracking and auto payment on delivery. Mobile app builder to create an app in 3 steps.
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