inheritance

import UIKit

class Vehicle {

    var currentSpeed = 0.0;

    //每呼叫一次就會被執行一次

    var description:String {

        return "現在的速度是每小時\(currentSpeed)";

    }

    func makeNoice() {

        //發出聲音

        

    }

}

//Bicycle 繼承 Vehicle

class Bicycle:Vehicle{

    var hasBasket = false;

}

let someVehicle = Vehicle();

let bicycle = Bicycle();

bicycle.currentSpeed = 15.0;

print("Bicycle:\(bicycle.description)");

class Tandem:Bicycle {

    var currentNumberOfPassengers = 0;

}

let tandem = Tandem();

tandem.hasBasket = true;

tandem.currentNumberOfPassengers = 2;

tandem.currentSpeed = 22.0;

//override

//Train 繼承 Vehicle，override method

class Train:Vehicle {

    override func makeNoice() {

        print("Choo Choo");

    }

}

let train = Train();

train.makeNoice();

//Car 繼承 Vehicle，override computed property

class Car:Vehicle{

    var gear = 1;

    override var description: String {

//        return "現在的速度是每小時\(currentSpeed)公里，" + "目前是\(gear)檔";

        return super.description + ",目前是\(gear)檔";

    }

}

let car = Car();

car.currentSpeed = 25.0;

car.gear = 3;

print("Car:\(car.description)");

//override property with observer

class AutomaticCar:Car {

    override var currentSpeed: Double{

        didSet{

            gear = Int(currentSpeed / 10.0) + 1

        }

    }

}

let automatic = AutomaticCar();

automatic.currentSpeed = 35.0;

print("automaticCar.\(automatic.description)");

Nginx限速

編輯站台設定檔，在Server區段內增加如下設定：
limit_rate 1024k;

重新啟動nginx

apache 限速

啟用mod_bw模組，並編輯mod_bw.conf，加入如下設定：
BandWidth    all 2621440

重新啟動apache

subscript

import UIKit

//subscript 快速存取實體的資料

/*語法：

 subscript(index:Int) -> Int{

    get{

        return Int;

    }

    set(newValue){

    }

 }

*/

struct TimesTable{

    let multiplier:Int;

    subscript(index:Int) -> Int{

        //只有get時，可以省略get語法

        return index * multiplier;

    }

}

let threeTimesTable = TimesTable(multiplier: 3);

print("6次的3是：\(threeTimesTable[6])");

var numberOfLegs = ["spider": 8, "ant": 6, "cat": 4];

//如果沒指定的key，就是新增

numberOfLegs["bird"] = 2;

struct Matrix{

    let rows:Int, columns:Int;

    var grid:[Double];

    

    init(rows:Int, columns:Int){

        self.rows = rows;

        self.columns = columns;

        grid = Array(repeating: 0.0, count: rows * columns);

    }

    func indexIsValid(row:Int, column:Int) -> Bool{

        return row >= 0 && row < rows && column >= 0 && column < columns;

    }

    subscript(row:Int, column:Int) -> Double{

        get{

            assert(indexIsValid(row: row, column: column),"Index out of range")

            return grid[(row * columns) + column]

        }

        

        set{

            assert(indexIsValid(row: row, column: column),"Index out of range")

            grid[(row * columns) + column] = newValue

        }

    }

}

var matrix = Matrix(rows: 2, columns: 3)

matrix[1,2] = 50.0

matrix[1,1] = 40.0

matrix[0,0] = 10.0

print(matrix.grid)

//print(matrix[20,20])

print(matrix[1,2]);

print(matrix[1,1]);

print(matrix[0,0]);