Compile and Execute Swift Online

import UIKit

// closures -> function without name
                // parameter     return type
let myClosure : (_ x:Int,_ y:Int) -> Int = {
     (x,y) in return x*y
}

print(myClosure(10,10))

let clousure:(_ n:Int,_ n1:Int) -> Int = {
    $0 * $1  // we not need to use return swift
}

// clousers may be optional
let myClosure1 : ((_ x:Int,_ y:Int) -> Int)? = {

    $0*$1
}

if let closure = myClosure1{
    print(closure(10,100))
}

myClosure1?(10,10) // if not nil the (10,10) execute

// closure can use as aparameter in function

func makeRequest(authenticated: @autoclosure ()->Bool){ // @autoclousure make { } by default
    if authenticated(){
        print("request suceesfully")
    }else {
        print("please sign in first")
    }
}
makeRequest(authenticated: true ) // or{true} but @autoclosure make {}
makeRequest(authenticated: false)

func make_request(name:String ,  authenticate1:()->Bool){
    if authenticate1(){
        print("Requesting --- ")
    }else{
        print("please sign in first")
    }
}

make_request(name: "mahmoud" ){true} // if the closure the last parameter in function
                                     // we can use this synax while calling function
makeRequest(authenticated: true)