Inside Swift’s inout parameters

Some of Swift’s parameters are not constants. This is why you need to know…

Functions usually pass parameters as constants in Swift, which means that they cannot be changed. If you could, you would need to return the result of your changes somehow. This is where the inout keyword comes into play, and lets you do exactly that.

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Difficulty: Beginner | Easy | Normal | Challenging

Prerequisites:

• Be able to produce a “Hello, World!” iOS application (guide HERE)
• Have some rudimentary understanding of functions (guide HERE)
• In a later example, knowledge of named parameters is assumed (guide HERE)
• Ideally understand the difference between pass by reference and pass by value (guide HERE), although the basics are covered within this article.

Terminology

Constant: A value that can not be amended during the normal execution of a program

inout parameter: A variable that is passed to a function, and if changed within the function the the changes are reflected in the original variable outside the function

in-place: On the spot