Defining functions, parameters, labels, default/variadic
Define functions with parameters, labels, default values, and variadic arguments.
Defining functions, parameters, labels, default/variadic is a free Swift Academy lesson on CoddyKit. This is lesson 1 of 3. Any 3 lessons of this learning path are free to read in full — after that, CoddyKit PRO unlocks every lesson, plus hands-on practice with a built-in code editor and a 24/7 AI tutor. It is part of the Swift Academy learning path, and your progress syncs across the web and the CoddyKit app. The Swift Academy course includes 3 lessons in total.
Intro
Functions group code into reusable blocks. You can pass data via parameters and return results.
Simple function
Define with func keyword. Call the function by its name.
func greet() {
print("Hello, Swift!")
}
greet()Parameters
Add parameters to pass input values into functions.
func square(number: Int) -> Int {
return number * number
}
print(square(number: 4))Labels
Parameter labels improve readability at the call site.
func multiply(a first: Int, b second: Int) -> Int {
return first * second
}
print(multiply(a: 3, b: 4))Default values
Default values let you omit arguments when calling.
func greet(name: String = "Guest") {
print("Hello, \\(name)")
}
greet()
greet(name: "Ada")Variadic parameters
Variadic parameters (with ...) accept many values as one array.
func sum(numbers: Int...) -> Int {
var total = 0
for n in numbers { total += n }
return total
}
print(sum(numbers: 1, 2, 3, 4))Variadic question
Quick check: Which syntax allows many values in one parameter?
Recap
Recap: Functions are defined with func, can take parameters, use labels, defaults, and variadic args for flexibility.
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Frequently Asked Questions
Is the “Defining functions, parameters, labels, default/variadic” lesson free?
Yes — any 3 lessons of the Swift Academy learning path, including “Defining functions, parameters, labels, default/variadic”, are free to read in full here on the web. After that, CoddyKit PRO unlocks every lesson, plus interactive practice with a built-in code editor and a 24/7 AI tutor. The Swift Academy course includes 3 lessons in total.
What will I learn in “Defining functions, parameters, labels, default/variadic”?
Define functions with parameters, labels, default values, and variadic arguments. You practise Swift Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Swift Academy?
No prior experience is required. Swift Academy on CoddyKit is structured for beginners through advanced learners, so you can start here or from the beginning and move at your own pace. This is lesson 1 of 3.
How long does the “Defining functions, parameters, labels, default/variadic” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Swift Academy lesson?
Yes. Every Swift Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Defining functions, parameters, labels, default/variadic
- Return values & multiple returns via tuples
- In-out params & basic error handling (throws)