The document provides an overview of functions in Swift including: - Function format with parameters, return types, and body - Calling functions and returning values - Functions that return tuples - External parameter names and shorthand names - Default parameter values - In-out parameters and call by reference - Function types as parameters and return types - Nested functions The document contains examples and explanations of each concept over 37 slides.

1. Welcome to Swift
3/5
func sayHello(name name: String) {
println("Hello (name)")
}
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2. •Function’s format
•Using the function
•Function with Tuple
•External Parameter Names
•Default Parameter Value
•Shorthand External Parameter Names
•Multiple Parameter
•In-Out Parameter
•Function type in Parameter and Return Type
다룰 내용
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3. Function’s format
func helloFunc(param:String)->String {
let hello = "hello "+param
return hello
}
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4. Function’s format
func helloFunc(param:String)->String {
let hello = "hello "+param
return hello
}
// declare function
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5. Function’s format
func helloFunc(param:String)->String {
let hello = "hello "+param
return hello
}
// function name
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6. Function’s format
func helloFunc(param:String)->String {
let hello = "hello "+param
return hello
}
// parameter’s name and parameter’s type
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7. Function’s format
func helloFunc(param:String)->String {
let hello = "hello "+param
return hello
}
// function’s return type
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8. Function’s format
func helloFunc(param:String)->String {
let hello = "hello "+param
return hello
}
//functions’s scope
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9. Function’s format
func helloFunc(param:String)->String {
let hello = "hello "+param
return hello
}
//function’s logic
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10. Function’s format
func helloFunc(param:String)->String {
let hello = "hello "+param
return hello
}
//return value in logic
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11. Using the function
var returnValue = helloFunc("Cody")
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12. Function with Tuple
import Foundation
func randomFunc(paramName:String)->(msg:String,random:Int) {
let hello = "hello "+paramName
let random = Int(arc4random()%8)
return (hello,random)
}
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13. Function with Tuple
import Foundation
func randomFunc(paramName:String)->(msg:String,random:Int) {
let hello = "hello "+paramName
let random = Int(arc4random()%8)
return (hello,random)
}
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14. Function with Tuple
import Foundation
func randomFunc(paramName:String)->(msg:String,random:Int) {
let hello = "hello "+paramName
let random = Int(arc4random()%8)
return (hello,random)
}
let tupleResult = randomFunc("Cody")
tupleResult.random
tupleResult.msg
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15. Function with external parameter names
func join(s1: String, s2: String, s3: String) -> String {
return s1 + s3 + s2
}
func join(header s1: String, tail s2: String, joiner s3: String) -> String {
return s1 + s3 + s2
}
// What is different?
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16. Function with external parameter names
func join(s1: String, s2: String, s3: String) -> String {
return s1 + s3 + s2
}
func join(header s1: String, tail s2: String, joiner s3: String) -> String {
return s1 + s3 + s2
}
// What is different?
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17. Function with external parameter names
func join(s1: String, s2: String, s3: String) -> String {
return s1 + s3 + s2
}
func join(header s1: String, tail s2: String, joiner s3: String) -> String {
return s1 + s3 + s2
}
// Header, tail and join will use for calling the function
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18. Function with external parameter names
func join(s1: String, s2: String, s3: String) -> String {
return s1 + s3 + s2
}
func join(header s1: String, tail s2: String, joiner s3: String) -> String {
return s1 + s3 + s2
}
// Header, tail and join will use for calling the function
join(header: "hello", tail: "world", joiner: ", ")
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19. Function with external parameter names
func join(s1: String, s2: String, s3: String) -> String {
return s1 + s3 + s2
}
func join(header s1: String, tail s2: String, joiner s3: String) -> String {
return s1 + s3 + s2
}
// Header, tail and join will use for calling the function
join(header: "hello", tail: "world", joiner: ", ")
// When call function without external paramter names
join("hello","world",", ")
Missing argument labels 'header:tail:joiner:' in call
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20. Function with shorthand external parameter names
func join(header s1: String, tail s2: String, joiner s3: String) -> String {
return s1 + s3 + s2
}
func join(#header: String, #tail: String, #joiner: String) -> String {
return header + joiner + tail
}
// What is different?
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21. Function with shorthand external parameter names
func join(header s1: String, tail s2: String, joiner s3: String) -> String {
return s1 + s3 + s2
}
func join(#header: String, #tail: String, #joiner: String) -> String {
return header + joiner + tail
}
// What is different?
// header s1 > #header
// tail s2 > #tail
// joiner s3 > #joiner
// External parameter name is equal with local parameter name.
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22. Function with default parameter value
func join(header s1: String, tail s2: String, joiner s3: String=" ") ->
String {
return s1 + s3 + s2
}
join(s1: "hello", s2: "world", s3: ", ")
join(s1: "hello", s2: "world")
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23. Function with constant value
func sayHello(let param:String)->String {
param = "test"
let hello = "hello "+param
return hello
}
let name = "Cody"
var returnValue = sayHello(name)
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24. Function with constant value
func helloFunc(let param:String)->String {
param = "test"
let hello = "hello "+param
return hello
}
let name = "Cody"
var returnValue = helloFunc(name)
Cannot assign to ‘let’ value ‘param’
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25. Function with multiple parameter
func sum(numbers: Int...) -> Int {
var total: Int = 0
for number in numbers {
total += number
}
return total
}
sum(1, 2, 3, 4, 5)
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26. Function with multiple parameter
func sum(numbers: Int...) -> Int {
var total: Int = 0
for number in numbers {
total += number
}
return total
}
sum(1, 2, 3, 4, 5)
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27. Function with in-out parameter
func swapTwoInt(inout a: Int, inout b: Int) {
let temp = a
a = b
b = temp
}
var numA = 1
var numB = 2
swapTwoInts(&numA,&numB)
numA
numB
// In C++ called “call by reference”
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28. Function with in-out parameter
// 물론 in-out parameter를 shorthands external parameter name과
// 함께 사용할 수도 있습니다.
func swapTwoInt(inout #a: Int, inout #b: Int) {
let temp = a
a = b
b = temp
}
var numA = 1
var numB = 2
swapTwoInts(a:&numA,b:&numB)
numA
numB
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29. Function with in-out parameter
func swapTwoInt(inout a: Int, inout b: Int) {
let temp = a
a = b
b = temp
}
var numA = 1
var numB = 2
swapTwoInts(&numA,&numB)
numA
numB
// In C++ called “call by reference”
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30. Function with in-out parameter
// 물론 in-out parameter를 shorthands external parameter name과
// 함께 사용할 수도 있습니다.
func swapTwoInt(inout #a: Int, inout #b: Int) {
let temp = a
a = b
b = temp
}
var numA = 1
var numB = 2
swapTwoInts(a:&numA,b:&numB)
numA
numB
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31. Function types
func addTwoInts(a: Int, b: Int) -> Int {
return a + b
}
var mathFunction: (Int, Int) -> Int = addTwoInts
mathFunction(10,20)
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32. Function types in parameter
func printFunctionResult(mathFunction: (Int, Int) -> Int) {
println("Result is (mathFunction(10,10))")
}
func addTwoInts(a: Int, b: Int) -> Int {
return a + b
}
var mathFunction: (Int, Int) -> Int = addTwoInts
printFunctionResult(mathFunction)
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33. Function types in parameter
// 사실 function을 변수에 assign해서 넘길 필요가 없어요
func printFunctionResult(mathFunction: (Int, Int) -> Int) {
println("Result is (mathFunction(10,10))")
}
func addTwoInts(a: Int, b: Int) -> Int {
return a + b
}
printFunctionResult(addTwoInts)
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34. Function types in return type
func stepForward(input: Int) -> Int {
return input + 1
}
func stepBackward(input: Int) -> Int {
return input - 1
}
func chooseStepFunction(backwards: Bool) -> (Int) -> Int {
return backwards ? stepBackward : stepForward
}
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35. Nested function
func chooseStepFunction(backwards: Bool) -> (Int) -> Int {
func stepForward(input: Int) -> Int {
return input + 1
}
func stepBackward(input: Int) -> Int {
return input - 1
}
return backwards ? stepBackward : stepForward
}
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36. 내일은?
• Enumeration
• Closures
• Structures and Classes
- Initializers and Deinitialization in Classes
- Properties
- Subscripts
- Inheritance
- Subclassing
- Overriding and Preventing Overrides
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37. 감사합니다.
let writer = ["Cody":"Yun"]
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