O'Reilly logo

Swift 3 ObjectOriented Programming - Second Edition by Gastón C. Hillar

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Adding methods with extensions

Sometimes, we would like to add methods to an existing class. We already know how to do this; we just need to go to its Swift source file and add a new method within the class body. However, sometimes, we cannot access the source code for the class, or it isn't convenient to make changes to it. A typical example of this situation is a class, struct, or any other type that is part of the standard language elements. For example, we might want to add a method that we can call in any Int value to initialize either a 2D or 3D point with all its elements set to the Int value.

The following lines declare a simple Point2D class that represents a mutable 2D point with the x and y elements. The class conforms to the CustomStringConvertible ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required