Introduction to generics

The concept of generics has been around for a while so it should not be a new concept to developers coming from languages such as Java or C#. Swift's implementation of generics is very similar to these languages. For those developers coming from other languages, such as Objective-C, which do not have generics, such as Java and C#, they might seem a bit foreign at first.

Generics allow us to write very flexible and reusable code that avoids duplication. With a type safe language, such as Swift, we often need to write functions or types that are valid for multiple types. For example, we might need to write a function that swaps the values of two variables; however, we may use this function to swap two strings types, two int types, and two double types. Without generics, we will need to write three separate functions; however, with generics, we can write one generic function to provide the swap functionality for multiple types. Generics allow us to tell a function or...