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Mastering Swift 5

You're reading from   Mastering Swift 5 Deep dive into the latest edition of the Swift programming language

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Product type Paperback
Published in Apr 2019
Publisher Packt
ISBN-13 9781789139860
Length 370 pages
Edition 5th Edition
Languages
Tools
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Author (1):
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Jon Hoffman Jon Hoffman
Author Profile Icon Jon Hoffman
Jon Hoffman
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Table of Contents (20) Chapters Close

Preface 1. Taking the First Steps with Swift FREE CHAPTER 2. Learning about Variables, Constants, Strings, and Operators 3. Optional Types 4. Using Swift Collections 5. Control Flow 6. Functions 7. Classes, Structures, and Protocols 8. Using Protocols and Protocol Extensions 9. Protocol Oriented Design 10. Generics 11. Availability and Error Handling 12. Custom Subscripting 13. Working with Closures 14. Concurrency and Parallelism in Swift 15. Custom Types 16. Memory Management 17. Swift Formatting and Style Guider 18. Adopting Design Patterns in Swift 19. Other Books You May Enjoy

Adding external parameter names

In the preceding examples in this section, we defined the parameters' names and value types in the same way we would define parameters in C code. In Swift, we are not limited to this syntax as we can also use external parameter names.

External parameter names are used to indicate the purpose of each parameter when we call a function. An external parameter name for each parameter needs to be defined in conjunction with its local parameter name. The external parameter name is added before the local parameter name in the function definition. The external and local parameter names are separated by a space.

Let's look at how to use external parameter names. But before we do, let's review how we have previously defined functions. In the following two examples, we will define a function without external parameter names, and then redefine...

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