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/*
Closure example 
(5) anonymous one-line closure
*/
let numbers = [12, 3, 6, 19]
let oddEven = numbers.map({ number in number % 2 == 0 ? "even" : "odd" })
/*
The value of oddEven:
["even", "odd", "even", "odd"]
*/

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/*
Closure example
(4)Anonymous closure in curly braces with "in"
*/

let nums = [20, 9, 17, 12]
let oddEven = nums.map({ (number: Int) -> String in
                       return number % 2 == 0 ? "even" : "odd"
                      })

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/* 
Closure examples
(3) Function as a parameter. 
*/
func testAtLeastOneMatch (list: [Int], condition: (Int) -> Bool) {
    for i in list {
        if condition(i) {
            return true
        }
    }

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/*
Closure examples
(2) return a function
*/

func makeAddition(toAdd: Int) -> ((Int) -> Int) {
    
    func add(base: Int) -> {
        return base + toAdd
    }

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/* 
Closure examples
(1) function in function. 
Inner function has access to variables of the outer function 
*/
func outer() -> Int {
    var outerVar = 5
    func inner() {
        outerVar += 5
    }

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// A typical Swift function signature
func myFunc(labelOfParam1 param1: String, _ param2: Int, param3: Float) -> Bool {
    print(param1)
    return param2 * Int(param3) > 0
}
// To call myFunc
myFunc(labelOfParam1: "Yo yo yo", 3, param3: 0.5)
/*
returns false 
Because casting the param3 Float 0.5 to Int give us 0

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func optionalTest() {
    let myName: String? = nil
    guard let name = myName
    else {
        print("I don't have a name")
        return //You need to return or throw an error, otherwise the compiler complains:
               //"error: 'guard' body may not fall through, consider using a 'return' or 'throw' to exit the scope
    }

    print("My name is \(name)")

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var myName: String?

if let name = myName {
    print("My name is \(name)")
} else {
    print("I don't have a name")
}
/*
I don't have a name
*/

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var nickName: String? = nil
var fullName: String = "Charlie Brown"
print("Hi, \(nickName ?? fullName)!")
/*
Hi, Charlie Brown!
*/

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var mightNotExist: String?
mightNotExist == nil // true

var notOptional: String
notOptional == nil // Error! connat access a non-optional before initialization