2019独角兽企业重金招聘Python工程师标准>>> 
swift扩展了很多功能和属性，有些也比较奇Ｐ。只有慢慢学习，通过经验慢慢总结了。
下面将初步学习一下类的写法。
码工，最大爱好就是看码，而不是文字，太枯燥。
//
// computer.swift
// swiftDemo
//
// Created by apple on 14-6-8.
// Copyright (c) 2014年 fengsh. All rights reserved.
/*
写本例子的目的在于快速学习swift类的写法，包括知识点：
1.属性设置
2.构造、释构
3.接口实现多态
4.函数的重载(重载很特别不需要overload关键词Delphi的朋友注意了)和重写(override)
5.类函数(静态成员函数)
6.各种函数的声明，带参，默认值，多个返回，多个输出参数，多个未确定参数的函数，内连函数等
7.函数类型变量，函数地址作为传参，返回函数地址（还未完工，学习中）
8.单例
9.swift新功能willset,didset @lazy 属性
10.（后续学习补充）
*/
import Foundation
var instance : Computer?
let unk = "unKnow"
//显示器屏幕宽高
struct MonitorWH {
var width = 0
var height = 0
var resolution = 0.0 //分辩率
}
//协义，接口，实现多重继承
protocol ProtocolComputer {
var price : Double {get} //只有get方法
func runComputer()
}
//计算机类型
enum ComputerType :Int
{
case none
case book //笔记本
case superBook //超级笔记本
case home //家庭电脑
}
func callbackWhenStarting()//computer:Computer
{
}
//计算机类
class Computer : NSObject,ProtocolComputer
{
var cpu = unk //cpu
var memory = unk //内存
var hardDisk = unk //硬盘
var monitor = unk //显示器
var cpName = unk //品牌
var computertype : ComputerType = .none
//@lazy //这关键词声明的有啥作用啊？？？？
//继承接口的属性
var price :Double = 0.0
//willset didset属性
var totalPrice: Int = 0 {
willSet(newTotalPrice) { //参数使用new+变量名且变量名首地址大写
println("准备将totalPrice值(原值为:\(totalPrice))设为: \(newTotalPrice)")
//to do somthing before set.
}
didSet {
if totalPrice > oldValue {
println("设置后新值比旧值增加了\(totalPrice - oldValue)")
}
}
}
//声明一个set,get属性
var computerPrice: Double {
get {
println("you call computerPrice.")
return price
}
set {
price = newValue
println("you set computerPrice value is \(price)")
}
}
//默认构造
init()
{
println("default creatrustor is called.")
}
//默认构造 不能和init()共存
// convenience init() {
// self.init(computerName: "unknow" ,price:0)
// }
//自定义构造函数
init(computerName:String,price:Double)
{
println("custom creatrustor is called.")
self.cpName = computerName
self.price = price
}
//释构
deinit {
println("this is destory?")
}
func description() -> String
{
//还真不知道怎么换行来写代码以前可以使用\现在被作参用了
return "Computer description : product \(self.cpName) ,type is \(self.computertype.toRaw()) , cpu is \(self.cpu) ,memory is \(self.memory),disk is \(self.hardDisk) ,monitor is \(self.monitor) ,price is \(self.price)"
}
//类函数 (OC 中的+号操作， c/c++ 中的static 函数)
class func shareInstance() -> Computer
{
return Computer()
}
//开机关机 (不带返回值函数)
func operationComputer(onOrOff : Bool)
{
if onOrOff
{
println("computer is starting")
}
else
{
println("computer is stopping")
}
}
//无参，无返回值函数
func computerRunning()
{
println("computer is running")
}
//多个返回值(即输出参数)
func getComputerConfig()->(cpu:String,hd:String,mem:String,mon:String)
{
return (self.cpu,self.hardDisk,self.memory,self.monitor)
}
//使用inout参数来作为输出参数
func getComputerConfig(inout cpu:String,inout hd:String,inout mem:String,inout mon:String)
{
cpu = self.cpu
hd = self.hardDisk
mem = self.memory
mon = self.monitor
}
//外部参数名函数（目的是让调用者更加清楚每个参数的具体函义）
//computerCPU,withComputerhardDisk,withComputerMemory,withComputerMonitor 这些都是外部参数名
//在调用时必须带上
func setComputerConfig(computerCPU cpu:String,withComputerhardDisk hd:String,
withComputerMemory mem:String,withComputerMonitor mon:String)
{
self.cpu = cpu
self.hardDisk = hd
self.memory = mem
self.monitor = mon
}
//使用#来把变量名提升了具有外部参数名作用的变量名，这样就不用再写一次外部参数名（在外部参数名与变量名相同时使用）
func setComputerConfig(#cpu:String,disk:String,mem:String,mon:String)
{
self.cpu = cpu
self.hardDisk = disk
self.memory = mem
self.monitor = mon
}
//参数的默认值
func macBookPro(pname:String = "Apple",cpu:String = "Intel Core I5",type:ComputerType,
mem:String = "2G",disk:String ,mon:String = "Intel HD Graphics 4000")
{
self.cpu = cpu
self.hardDisk = disk
self.memory = mem
self.monitor = mon
self.cpName = pname
self.computertype = type
}
//可变参数
func usbNumbers(usbs:String...) -> String
{
var ret : String = ""
for usb in usbs
{
println(usb)
ret += (usb + ",")
}
return ret
}
//常量参数、变量参数
//尽管函数内部修改了version 但并不影响原来外部设定的值
func lookWindowsVersion(var version:String) ->String
{
version = "default windows " + version
return version
}
//mutating func
func getResolution(pname:String) -> MonitorWH
{
var mt = MonitorWH(width: 1364,height: 1280,resolution: 16/9)
if pname == "Phripse"
{
mt = MonitorWH(width: 5555,height: 3333,resolution: 29/10)
}
return mt
}
//函数作为参数传参
//var callbackWhenStarting : ()->() = callbackWhenStarting
//函数作为返回值
//函数作为变量定义
//嵌套函数
func openTask()
{
func openOtherTask()
{
println("open other task")
}
println("open task")
}
//函数重写
func lookComputerBasicHardInfo(computer:Computer)
{
}
//接口实现
func runComputer()
{
println("Computer run.")
}
}
class Lenove : Computer
{
override func lookComputerBasicHardInfo(computer:Computer)
{
if computer is Lenove //is as 操作。
{
println("这是联想")
}
}
}
调用ＤＥＭＯ：
//var cpt = Computer() //调用默认构造
var cpt = Computer(computerName: "Apple",price:12000) //调用自定义构造
println(cpt.description)
println(cpt.getComputerConfig())
//属性测试
println("价钱为:\(cpt.computerPrice)")
cpt.computerPrice = 2000.0;
println("设置后的价钱为:\(cpt.computerPrice)")
//测试willset didset
cpt.totalPrice = 100;
cpt.totalPrice = 400;
cpt.totalPrice = 900;
var a = "",b = "",c = "",d = ""
cpt.getComputerConfig(&a,hd: &b,mem: &c,mon: &d)
println("a=\(a),b=\(b),c=\(c),d=\(d)")
cpt.setComputerConfig(computerCPU :"inter i5", withComputerhardDisk:"WD 500",
withComputerMemory:"4G",withComputerMonitor:"Phripse")
println("最新配置:\(cpt.description)")
cpt.setComputerConfig(cpu: "AMD", disk: "HD 1T", mem: "8G", mon: "SamSung")
println("最新配置:\(cpt.description)")
//使用缺省值调用函数
cpt.macBookPro(type: ComputerType.book,disk: "5")
println("平果配置:\(cpt.description)")
let usbSupportType = cpt.usbNumbers("2.0","3.0")
println("支持USB接口:\(usbSupportType))")
let extentUsbType = cpt.usbNumbers("5.0")
println("扩展USB接口:\(extentUsbType)")
var version = "xp 3";
let newversion = cpt.lookWindowsVersion(version);
println(version)
println(newversion)
输出：
custom creatrustor is called.
Computer description : product Apple ,type is 0 , cpu is unKnow ,memory is unKnow,disk is unKnow ,monitor is unKnow ,price is 12000.0
(unKnow, unKnow, unKnow, unKnow)
you call computerPrice.
价钱为:12000.0
you set computerPrice value is 2000.0
you call computerPrice.
设置后的价钱为:2000.0
准备将totalPrice值(原值为:0)设为: 100
设置后新值比旧值增加了100
准备将totalPrice值(原值为:100)设为: 400
设置后新值比旧值增加了300
准备将totalPrice值(原值为:400)设为: 900
设置后新值比旧值增加了500
a=unKnow,b=unKnow,c=unKnow,d=unKnow
最新配置:Computer description : product Apple ,type is 0 , cpu is inter i5 ,memory is 4G,disk is WD 500 ,monitor is Phripse ,price is 2000.0
最新配置:Computer description : product Apple ,type is 0 , cpu is AMD ,memory is 8G,disk is HD 1T ,monitor is SamSung ,price is 2000.0
平果配置:Computer description : product Apple ,type is 1 , cpu is Intel Core I5 ,memory is 2G,disk is 5 ,monitor is Intel HD Graphics 4000 ,price is 2000.0
2.0
3.0
支持USB接口:2.0,3.0,)
5.0
扩展USB接口:5.0,
xp 3
default windows xp 3
this is destory?
样子最好自己写一个从过种中去学习。光看，也许还不清楚是什么。
谢谢大家，因为是英文文档，看得我头也比较痛，有些要猜和运行来理解，还有些没有完善有点乱。有些没有搞懂所以就没有整理好。
大家共同学习，共同进步。