iOS_函數的學習_閉包（Closurs)的學習及概念

函數的使用方式

//

//  ViewController.swift

//  ios_Optional_

//

//  Created by stu_11 on 2017/4/14.

//  Copyright © 2017年 mcu. All rights reserved.

//

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {

        super.viewDidLoad()

        // Do any additional setup after loading the view, typically from a nib.

        

        

        //Optional 的 錯誤 不能指定  nil

        //var message: String = "Swift is awesome!!"

        //message = nil

        

        

        SayHi()

        

        SayHello(name: "Samuel")

        

        say(name: "Simon", greeting: "Mary")

        

    }

    override func didReceiveMemoryWarning() {

        super.didReceiveMemoryWarning()

        // Dispose of any resources that can be recreated.

    }

    

    

    //無參數輸入的函數

    func SayHi(){

        print("Hi everyone!!!")

    }

    

    //有參數輸入的函數（單一個）

    func SayHello(name: String)

    {

        print("Hello \(name)")

    }

    //多個參數輸入的函數

    func say(name:String , greeting: String){

        print("\(greeting) send gift to \(name)")

    }

    

}

======================================================================

//

//  ViewController.swift

//  ios_Optional_

//

//  Created by stu_11 on 2017/4/14.

//  Copyright © 2017年 mcu. All rights reserved.

//

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {

        super.viewDidLoad()

        // Do any additional setup after loading the view, typically from a nib.

        

        if let stock = findStockCode(company: "Apple"){

            if let sharePrice = stock.price {

                let totalCost = sharePrice*100

                print(totalCost)

            }

        }

        

    }

    override func didReceiveMemoryWarning() {

        super.didReceiveMemoryWarning()

        // Dispose of any resources that can be recreated.

    }

    

    //  函數 寫在class ViewController: UIViewController

    func findStockCode(company: String)-> Stock?{

        if (company == "Apple"){

            let aapl: Stock = Stock()

            aapl.code = "AAPL"

            aapl.price = 90.76

            return aapl

        }

        else if(company =="Google")

        {

            let goog: Stock = Stock()

            goog.code = "GOOG"

            goog.price = 556.36

            return goog

        }

        return nil

    }

    

    

}

class Stock{

    var code: String?

    var price:Double?

}