{"id":548,"date":"2018-02-23T23:39:13","date_gmt":"2018-02-23T15:39:13","guid":{"rendered":"http:\/\/60.205.208.74\/2018\/02\/23\/swift-%e5%8d%8f%e8%ae%ae\/"},"modified":"2018-02-23T23:39:13","modified_gmt":"2018-02-23T15:39:13","slug":"swift-%e5%8d%8f%e8%ae%ae","status":"publish","type":"post","link":"https:\/\/www.puzi7.net\/?p=548","title":{"rendered":"Swift \u534f\u8bae"},"content":{"rendered":"<span itemprop=\"description\"><div class=\"article-body\">\n<div class=\"article-intro\" id=\"content\">\n<h1>Swift \u534f\u8bae<\/h1>\n<p>\u534f\u8bae\u89c4\u5b9a\u4e86\u7528\u6765\u5b9e\u73b0\u67d0\u4e00\u7279\u5b9a\u529f\u80fd\u6240\u5fc5\u9700\u7684\u65b9\u6cd5\u548c\u5c5e\u6027\u3002<\/p>\n<p>\u4efb\u610f\u80fd\u591f\u6ee1\u8db3\u534f\u8bae\u8981\u6c42\u7684\u7c7b\u578b\u88ab\u79f0\u4e3a\u9075\u5faa(conform)\u8fd9\u4e2a\u534f\u8bae\u3002<\/p>\n<p>\u7c7b\uff0c\u7ed3\u6784\u4f53\u6216\u679a\u4e3e\u7c7b\u578b\u90fd\u53ef\u4ee5\u9075\u5faa\u534f\u8bae\uff0c\u5e76\u63d0\u4f9b\u5177\u4f53\u5b9e\u73b0\u6765\u5b8c\u6210\u534f\u8bae\u5b9a\u4e49\u7684\u65b9\u6cd5\u548c\u529f\u80fd\u3002<\/p>\n<h3>\u8bed\u6cd5<\/h3>\n<p>\u534f\u8bae\u7684\u8bed\u6cd5\u683c\u5f0f\u5982\u4e0b\uff1a<\/p>\n<pre>\nprotocol SomeProtocol {\n    \/\/ \u534f\u8bae\u5185\u5bb9\n}\n<\/pre>\n<p>\u8981\u4f7f\u7c7b\u9075\u5faa\u67d0\u4e2a\u534f\u8bae\uff0c\u9700\u8981\u5728\u7c7b\u578b\u540d\u79f0\u540e\u52a0\u4e0a\u534f\u8bae\u540d\u79f0\uff0c\u4e2d\u95f4\u4ee5\u5192\u53f7:\u5206\u9694\uff0c\u4f5c\u4e3a\u7c7b\u578b\u5b9a\u4e49\u7684\u4e00\u90e8\u5206\u3002\u9075\u5faa\u591a\u4e2a\u534f\u8bae\u65f6\uff0c\u5404\u534f\u8bae\u4e4b\u95f4\u7528\u9017\u53f7,\u5206\u9694\u3002<\/p>\n<pre>\nstruct SomeStructure: FirstProtocol, AnotherProtocol {\n    \/\/ \u7ed3\u6784\u4f53\u5185\u5bb9\n}\n<\/pre>\n<p>\u5982\u679c\u7c7b\u5728\u9075\u5faa\u534f\u8bae\u7684\u540c\u65f6\u62e5\u6709\u7236\u7c7b\uff0c\u5e94\u8be5\u5c06\u7236\u7c7b\u540d\u653e\u5728\u534f\u8bae\u540d\u4e4b\u524d\uff0c\u4ee5\u9017\u53f7\u5206\u9694\u3002<\/p>\n<pre>\nclass SomeClass: SomeSuperClass, FirstProtocol, AnotherProtocol {\n    \/\/ \u7c7b\u7684\u5185\u5bb9\n}\n<\/pre>\n<hr>\n<h2>\u5bf9\u5c5e\u6027\u7684\u89c4\u5b9a<\/h2>\n<p>\u534f\u8bae\u7528\u4e8e\u6307\u5b9a\u7279\u5b9a\u7684\u5b9e\u4f8b\u5c5e\u6027\u6216\u7c7b\u5c5e\u6027\uff0c\u800c\u4e0d\u7528\u6307\u5b9a\u662f\u5b58\u50a8\u578b\u5c5e\u6027\u6216\u8ba1\u7b97\u578b\u5c5e\u6027\u3002\u6b64\u5916\u8fd8\u5fc5\u987b\u6307\u660e\u662f\u53ea\u8bfb\u7684\u8fd8\u662f\u53ef\u8bfb\u53ef\u5199\u7684\u3002<\/p>\n<p>\u534f\u8bae\u4e2d\u7684\u901a\u5e38\u7528var\u6765\u58f0\u660e\u53d8\u91cf\u5c5e\u6027\uff0c\u5728\u7c7b\u578b\u58f0\u660e\u540e\u52a0\u4e0a{ set get }\u6765\u8868\u793a\u5c5e\u6027\u662f\u53ef\u8bfb\u53ef\u5199\u7684\uff0c\u53ea\u8bfb\u5c5e\u6027\u5219\u7528{ get }\u6765\u8868\u793a\u3002<\/p>\n<pre>\nprotocol classa {\n    \n    var marks: Int { get set }\n    var result: Bool { get }\n    \n    func attendance() -&gt; String\n    func markssecured() -&gt; String\n    \n}\n\nprotocol classb: classa {\n    \n    var present: Bool { get set }\n    var subject: String { get set }\n    var stname: String { get set }\n    \n}\n\nclass classc: classb {\n    var marks = 96\n    let result = true\n    var present = false\n    var subject = \"Swift \u534f\u8bae\"\n    var stname = \"Protocols\"\n    \n    func attendance() -&gt; String {\n        return \"The \\(stname) has secured 99% attendance\"\n    }\n    \n    func markssecured() -&gt; String {\n        return \"\\(stname) has scored \\(marks)\"\n    }\n}\n\nlet studdet = classc()\nstuddet.stname = \"Swift\"\nstuddet.marks = 98\nstuddet.markssecured()\n\nprint(studdet.marks)\nprint(studdet.result)\nprint(studdet.present)\nprint(studdet.subject)\nprint(studdet.stname)\n<\/pre>\n<p>\u4ee5\u4e0a\u7a0b\u5e8f\u6267\u884c\u8f93\u51fa\u7ed3\u679c\u4e3a\uff1a<\/p>\n<pre>\n98\ntrue\nfalse\nSwift \u534f\u8bae\nSwift\n<\/pre>\n<hr>\n<h2>\u5bf9 Mutating \u65b9\u6cd5\u7684\u89c4\u5b9a<\/h2>\n<p>\u6709\u65f6\u9700\u8981\u5728\u65b9\u6cd5\u4e2d\u6539\u53d8\u5b83\u7684\u5b9e\u4f8b\u3002<\/p>\n<p>\u4f8b\u5982\uff0c\u503c\u7c7b\u578b(\u7ed3\u6784\u4f53\uff0c\u679a\u4e3e)\u7684\u5b9e\u4f8b\u65b9\u6cd5\u4e2d\uff0c\u5c06mutating\u5173\u952e\u5b57\u4f5c\u4e3a\u51fd\u6570\u7684\u524d\u7f00\uff0c\u5199\u5728func\u4e4b\u524d\uff0c\u8868\u793a\u53ef\u4ee5\u5728\u8be5\u65b9\u6cd5\u4e2d\u4fee\u6539\u5b83\u6240\u5c5e\u7684\u5b9e\u4f8b\u53ca\u5176\u5b9e\u4f8b\u5c5e\u6027\u7684\u503c\u3002\n<\/p>\n<pre>\nprotocol daysofaweek {\n    mutating func show()\n}\n\nenum days: daysofaweek {\n    case sun, mon, tue, wed, thurs, fri, sat\n    mutating func show() {\n        switch self {\n        case .sun:\n            self = .sun\n            print(\"Sunday\")\n        case .mon:\n            self = .mon\n            print(\"Monday\")\n        case .tue:\n            self = .tue\n            print(\"Tuesday\")\n        case .wed:\n            self = .wed\n            print(\"Wednesday\")\n        case .thurs:\n            self = .thurs\n            print(\"Wednesday\")\n        case .fri:\n            self = .fri\n            print(\"Wednesday\")\n        case .sat:\n            self = .sat\n            print(\"Saturday\")\n        default:\n            print(\"NO Such Day\")\n        }\n    }\n}\n\nvar res = days.wed\nres.show()\n<\/pre>\n<p>\u4ee5\u4e0a\u7a0b\u5e8f\u6267\u884c\u8f93\u51fa\u7ed3\u679c\u4e3a\uff1a<\/p>\n<pre>\nWednesday\n<\/pre>\n<hr>\n<h2>\u5bf9\u6784\u9020\u5668\u7684\u89c4\u5b9a<\/h2>\n<p>\u534f\u8bae\u53ef\u4ee5\u8981\u6c42\u5b83\u7684\u9075\u5faa\u8005\u5b9e\u73b0\u6307\u5b9a\u7684\u6784\u9020\u5668\u3002<\/p>\n<p>\u4f60\u53ef\u4ee5\u50cf\u4e66\u5199\u666e\u901a\u7684\u6784\u9020\u5668\u90a3\u6837\uff0c\u5728\u534f\u8bae\u7684\u5b9a\u4e49\u91cc\u5199\u4e0b\u6784\u9020\u5668\u7684\u58f0\u660e\uff0c\u4f46\u4e0d\u9700\u8981\u5199\u82b1\u62ec\u53f7\u548c\u6784\u9020\u5668\u7684\u5b9e\u4f53\uff0c\u8bed\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre>\nprotocol SomeProtocol {\n   init(someParameter: Int)\n}\n<\/pre>\n<h3>\u5b9e\u4f8b<\/h3>\n<pre>\nprotocol tcpprotocol {\n   init(aprot: Int)\n}\n<\/pre>\n<hr>\n<h2>\u534f\u8bae\u6784\u9020\u5668\u89c4\u5b9a\u5728\u7c7b\u4e2d\u7684\u5b9e\u73b0<\/h2>\n<p>\u4f60\u53ef\u4ee5\u5728\u9075\u5faa\u8be5\u534f\u8bae\u7684\u7c7b\u4e2d\u5b9e\u73b0\u6784\u9020\u5668\uff0c\u5e76\u6307\u5b9a\u5176\u4e3a\u7c7b\u7684\u6307\u5b9a\u6784\u9020\u5668\u6216\u8005\u4fbf\u5229\u6784\u9020\u5668\u3002\u5728\u8fd9\u4e24\u79cd\u60c5\u51b5\u4e0b\uff0c\u4f60\u90fd\u5fc5\u987b\u7ed9\u6784\u9020\u5668\u5b9e\u73b0\u6807\u4e0a&#8221;required&#8221;\u4fee\u9970\u7b26\uff1a<\/p>\n<pre>\nclass SomeClass: SomeProtocol {\n   required init(someParameter: Int) {\n      \/\/ \u6784\u9020\u5668\u5b9e\u73b0\n   }\n}\n\nprotocol tcpprotocol {\n   init(aprot: Int)\n}\n\nclass tcpClass: tcpprotocol {\n   required init(aprot: Int) {\n   }\n}\n<\/pre>\n<p>\u4f7f\u7528required\u4fee\u9970\u7b26\u53ef\u4ee5\u4fdd\u8bc1\uff1a\u6240\u6709\u7684\u9075\u5faa\u8be5\u534f\u8bae\u7684\u5b50\u7c7b\uff0c\u540c\u6837\u80fd\u4e3a\u6784\u9020\u5668\u89c4\u5b9a\u63d0\u4f9b\u4e00\u4e2a\u663e\u5f0f\u7684\u5b9e\u73b0\u6216\u7ee7\u627f\u5b9e\u73b0\u3002<\/p>\n<p>\u5982\u679c\u4e00\u4e2a\u5b50\u7c7b\u91cd\u5199\u4e86\u7236\u7c7b\u7684\u6307\u5b9a\u6784\u9020\u5668\uff0c\u5e76\u4e14\u8be5\u6784\u9020\u5668\u9075\u5faa\u4e86\u67d0\u4e2a\u534f\u8bae\u7684\u89c4\u5b9a\uff0c\u90a3\u4e48\u8be5\u6784\u9020\u5668\u7684\u5b9e\u73b0\u9700\u8981\u88ab\u540c\u65f6\u6807\u793arequired\u548coverride\u4fee\u9970\u7b26\uff1a<\/p>\n<pre>\nprotocol tcpprotocol {\n    init(no1: Int)\n}\n\nclass mainClass {\n    var no1: Int \/\/ \u5c40\u90e8\u53d8\u91cf\n    init(no1: Int) {\n        self.no1 = no1 \/\/ \u521d\u59cb\u5316\n    }\n}\n\nclass subClass: mainClass, tcpprotocol {\n    var no2: Int\n    init(no1: Int, no2 : Int) {\n        self.no2 = no2\n        super.init(no1:no1)\n    }\n    \/\/ \u56e0\u4e3a\u9075\u5faa\u534f\u8bae\uff0c\u9700\u8981\u52a0\u4e0a\"required\"; \u56e0\u4e3a\u7ee7\u627f\u81ea\u7236\u7c7b\uff0c\u9700\u8981\u52a0\u4e0a\"override\"\n    required override convenience init(no1: Int)  {\n        self.init(no1:no1, no2:0)\n    }\n}\nlet res = mainClass(no1: 20)\nlet show = subClass(no1: 30, no2: 50)\n\nprint(\"res is: \\(res.no1)\")\nprint(\"res is: \\(show.no1)\")\nprint(\"res is: \\(show.no2)\")\n<\/pre>\n<p>\u4ee5\u4e0a\u7a0b\u5e8f\u6267\u884c\u8f93\u51fa\u7ed3\u679c\u4e3a\uff1a<\/p>\n<pre>\nres is: 20\nres is: 30\nres is: 50\n<\/pre>\n<hr>\n<h2>\u534f\u8bae\u7c7b\u578b<\/h2>\n<p>\u5c3d\u7ba1\u534f\u8bae\u672c\u8eab\u5e76\u4e0d\u5b9e\u73b0\u4efb\u4f55\u529f\u80fd\uff0c\u4f46\u662f\u534f\u8bae\u53ef\u4ee5\u88ab\u5f53\u505a\u7c7b\u578b\u6765\u4f7f\u7528\u3002<\/p>\n<p>\u534f\u8bae\u53ef\u4ee5\u50cf\u5176\u4ed6\u666e\u901a\u7c7b\u578b\u4e00\u6837\u4f7f\u7528\uff0c\u4f7f\u7528\u573a\u666f:<\/p>\n<ul>\n<li>\u4f5c\u4e3a\u51fd\u6570\u3001\u65b9\u6cd5\u6216\u6784\u9020\u5668\u4e2d\u7684\u53c2\u6570\u7c7b\u578b\u6216\u8fd4\u56de\u503c\u7c7b\u578b<\/li>\n<li>\u4f5c\u4e3a\u5e38\u91cf\u3001\u53d8\u91cf\u6216\u5c5e\u6027\u7684\u7c7b\u578b<\/li>\n<li>\u4f5c\u4e3a\u6570\u7ec4\u3001\u5b57\u5178\u6216\u5176\u4ed6\u5bb9\u5668\u4e2d\u7684\u5143\u7d20\u7c7b\u578b<\/li>\n<\/ul>\n<h3>\u5b9e\u4f8b<\/h3>\n<pre>\nprotocol Generator {\n    associatedtype members\n    func next() -&gt; members?\n}\n\nvar items = [10,20,30].makeIterator()\nwhile let x = items.next() {\n    print(x)\n}\n\nfor lists in [1,2,3].map( {i in i*5}) {\n    print(lists)\n}\n\nprint([100,200,300])\nprint([1,2,3].map({i in i*10}))\n<\/pre>\n<p>\u4ee5\u4e0a\u7a0b\u5e8f\u6267\u884c\u8f93\u51fa\u7ed3\u679c\u4e3a\uff1a<\/p>\n<pre>\n10\n20\n30\n5\n10\n15\n[100, 200, 300]\n[10, 20, 30]\n<\/pre>\n<hr>\n<h2>\u5728\u6269\u5c55\u4e2d\u6dfb\u52a0\u534f\u8bae\u6210\u5458<\/h2>\n<p>\u6211\u4eec\u53ef\u4ee5\u53ef\u4ee5\u901a\u8fc7\u6269\u5c55\u6765\u6269\u5145\u5df2\u5b58\u5728\u7c7b\u578b( \u7c7b\uff0c\u7ed3\u6784\u4f53\uff0c\u679a\u4e3e\u7b49)\u3002\n<\/p>\n<p>\u6269\u5c55\u53ef\u4ee5\u4e3a\u5df2\u5b58\u5728\u7684\u7c7b\u578b\u6dfb\u52a0\u5c5e\u6027\uff0c\u65b9\u6cd5\uff0c\u4e0b\u6807\u811a\u672c\uff0c\u534f\u8bae\u7b49\u6210\u5458\u3002<\/p>\n<pre>\nprotocol AgeClasificationProtocol {\n   var age: Int { get }\n   func agetype() -&gt; String\n}\n\nclass Person {\n   let firstname: String\n   let lastname: String\n   var age: Int\n   init(firstname: String, lastname: String) {\n      self.firstname = firstname\n      self.lastname = lastname\n      self.age = 10\n   }\n}\n\nextension Person : AgeClasificationProtocol {\n   func fullname() -&gt; String {\n      var c: String\n      c = firstname + \" \" + lastname\n      return c\n   }\n   \n   func agetype() -&gt; String {\n      switch age {\n      case 0...2:\n         return \"Baby\"\n      case 2...12:\n         return \"Child\"\n      case 13...19:\n         return \"Teenager\"\n      case let x where x &gt; 65:\n         return \"Elderly\"\n      default:\n         return \"Normal\"\n      }\n   }\n}<\/pre>\n<hr>\n<h2>\u534f\u8bae\u7684\u7ee7\u627f<\/h2>\n<p>\u534f\u8bae\u80fd\u591f\u7ee7\u627f\u4e00\u4e2a\u6216\u591a\u4e2a\u5176\u4ed6\u534f\u8bae\uff0c\u53ef\u4ee5\u5728\u7ee7\u627f\u7684\u534f\u8bae\u57fa\u7840\u4e0a\u589e\u52a0\u65b0\u7684\u5185\u5bb9\u8981\u6c42\u3002<\/p>\n<p>\u534f\u8bae\u7684\u7ee7\u627f\u8bed\u6cd5\u4e0e\u7c7b\u7684\u7ee7\u627f\u76f8\u4f3c\uff0c\u591a\u4e2a\u88ab\u7ee7\u627f\u7684\u534f\u8bae\u95f4\u7528\u9017\u53f7\u5206\u9694\uff1a<\/p>\n<pre>\nprotocol InheritingProtocol: SomeProtocol, AnotherProtocol {\n    \/\/ \u534f\u8bae\u5b9a\u4e49\n}\n<\/pre>\n<h3>\u5b9e\u4f8b<\/h3>\n<pre>\nprotocol Classa {\n    var no1: Int { get set }\n    func calc(sum: Int)\n}\n\nprotocol Result {\n    func print(target: Classa)\n}\n\nclass Student2: Result {\n    func print(target: Classa) {\n        target.calc(1)\n    }\n}\n\nclass Classb: Result {\n    func print(target: Classa) {\n        target.calc(5)\n    }\n}\n\nclass Student: Classa {\n    var no1: Int = 10\n    \n    func calc(sum: Int) {\n        no1 -= sum\n        print(\"\u5b66\u751f\u5c1d\u8bd5 \\(sum) \u6b21\u901a\u8fc7\")\n        \n        if no1 &lt;= 0 {\n            print(\"\u5b66\u751f\u7f3a\u5e2d\u8003\u8bd5\")\n        }\n    }\n}\n\nclass Player {\n    var stmark: Result!\n    \n    init(stmark: Result) {\n        self.stmark = stmark\n    }\n    \n    func print(target: Classa) {\n        stmark.print(target)\n    }\n}\n\nvar marks = Player(stmark: Student2())\nvar marksec = Student()\n\nmarks.print(marksec)\nmarks.print(marksec)\nmarks.print(marksec)\nmarks.stmark = Classb()\nmarks.print(marksec)\nmarks.print(marksec)\nmarks.print(marksec)\n<\/pre>\n<p>\u4ee5\u4e0a\u7a0b\u5e8f\u6267\u884c\u8f93\u51fa\u7ed3\u679c\u4e3a\uff1a<\/p>\n<pre>\n\u5b66\u751f\u5c1d\u8bd5 1 \u6b21\u901a\u8fc7\n\u5b66\u751f\u5c1d\u8bd5 1 \u6b21\u901a\u8fc7\n\u5b66\u751f\u5c1d\u8bd5 1 \u6b21\u901a\u8fc7\n\u5b66\u751f\u5c1d\u8bd5 5 \u6b21\u901a\u8fc7\n\u5b66\u751f\u5c1d\u8bd5 5 \u6b21\u901a\u8fc7\n\u5b66\u751f\u7f3a\u5e2d\u8003\u8bd5\n\u5b66\u751f\u5c1d\u8bd5 5 \u6b21\u901a\u8fc7\n\u5b66\u751f\u7f3a\u5e2d\u8003\u8bd5\n<\/pre>\n<hr>\n<h2>\u7c7b\u4e13\u5c5e\u534f\u8bae<\/h2>\n<p>\u4f60\u53ef\u4ee5\u5728\u534f\u8bae\u7684\u7ee7\u627f\u5217\u8868\u4e2d,\u901a\u8fc7\u6dfb\u52a0class\u5173\u952e\u5b57,\u9650\u5236\u534f\u8bae\u53ea\u80fd\u9002\u914d\u5230\u7c7b\uff08class\uff09\u7c7b\u578b\u3002<\/p>\n<p>\u8be5class\u5173\u952e\u5b57\u5fc5\u987b\u662f\u7b2c\u4e00\u4e2a\u51fa\u73b0\u5728\u534f\u8bae\u7684\u7ee7\u627f\u5217\u8868\u4e2d\uff0c\u5176\u540e\uff0c\u624d\u662f\u5176\u4ed6\u7ee7\u627f\u534f\u8bae\u3002\u683c\u5f0f\u5982\u4e0b\uff1a<\/p>\n<pre>\nprotocol SomeClassOnlyProtocol: class, SomeInheritedProtocol {\n    \/\/ \u534f\u8bae\u5b9a\u4e49\n}\n<\/pre>\n<h3>\u5b9e\u4f8b<\/h3>\n<pre>\nprotocol TcpProtocol {\n    init(no1: Int)\n}\n\nclass MainClass {\n    var no1: Int \/\/ \u5c40\u90e8\u53d8\u91cf\n    init(no1: Int) {\n        self.no1 = no1 \/\/ \u521d\u59cb\u5316\n    }\n}\n\nclass SubClass: MainClass, TcpProtocol {\n    var no2: Int\n    init(no1: Int, no2 : Int) {\n        self.no2 = no2\n        super.init(no1:no1)\n    }\n    \/\/ \u56e0\u4e3a\u9075\u5faa\u534f\u8bae\uff0c\u9700\u8981\u52a0\u4e0a\"required\"; \u56e0\u4e3a\u7ee7\u627f\u81ea\u7236\u7c7b\uff0c\u9700\u8981\u52a0\u4e0a\"override\"\n    required override convenience init(no1: Int)  {\n        self.init(no1:no1, no2:0)\n    }\n}\n\nlet res = MainClass(no1: 20)\nlet show = SubClass(no1: 30, no2: 50)\n\nprint(\"res is: \\(res.no1)\")\nprint(\"res is: \\(show.no1)\")\nprint(\"res is: \\(show.no2)\")\n<\/pre>\n<p>\u4ee5\u4e0a\u7a0b\u5e8f\u6267\u884c\u8f93\u51fa\u7ed3\u679c\u4e3a\uff1a<\/p>\n<pre>\nres is: 20\nres is: 30\nres is: 50\n<\/pre>\n<hr>\n<h2>\u534f\u8bae\u5408\u6210<\/h2>\n<p>Swift \u652f\u6301\u5408\u6210\u591a\u4e2a\u534f\u8bae\uff0c\u8fd9\u5728\u6211\u4eec\u9700\u8981\u540c\u65f6\u9075\u5faa\u591a\u4e2a\u534f\u8bae\u65f6\u975e\u5e38\u6709\u7528\u3002<\/p>\n<p>\u8bed\u6cd5\u683c\u5f0f\u5982\u4e0b\uff1a<\/p>\n<pre>\nprotocol Stname {\n    var name: String { get }\n}\n\nprotocol Stage {\n    var age: Int { get }\n}\n\nstruct Person: Stname, Stage {\n    var name: String\n    var age: Int\n}\n\nfunc show(celebrator: Stname &amp; Stage) {\n    print(\"\\(celebrator.name) is \\(celebrator.age) years old\")\n}\n\nlet studname = Person(name: \"Priya\", age: 21)\nprint(studname)\n\nlet stud = Person(name: \"Rehan\", age: 29)\nprint(stud)\n\nlet student = Person(name: \"Roshan\", age: 19)\nprint(student)\n<\/pre>\n<p>\u4ee5\u4e0a\u7a0b\u5e8f\u6267\u884c\u8f93\u51fa\u7ed3\u679c\u4e3a\uff1a<\/p>\n<pre>\nPerson(name: \"Priya\", age: 21)\nPerson(name: \"Rehan\", age: 29)\nPerson(name: \"Roshan\", age: 19)\n<\/pre>\n<hr>\n<h2>\u68c0\u9a8c\u534f\u8bae\u7684\u4e00\u81f4\u6027<\/h2>\n<p>\u4f60\u53ef\u4ee5\u4f7f\u7528is\u548cas\u64cd\u4f5c\u7b26\u6765\u68c0\u67e5\u662f\u5426\u9075\u5faa\u67d0\u4e00\u534f\u8bae\u6216\u5f3a\u5236\u8f6c\u5316\u4e3a\u67d0\u4e00\u7c7b\u578b\u3002<\/p>\n<ul>\n<li><code>is<\/code>\u64cd\u4f5c\u7b26\u7528\u6765\u68c0\u67e5\u5b9e\u4f8b\u662f\u5426<code>\u9075\u5faa<\/code>\u4e86\u67d0\u4e2a<code>\u534f\u8bae<\/code>\u3002<\/li>\n<li><code>as?<\/code>\u8fd4\u56de\u4e00\u4e2a\u53ef\u9009\u503c\uff0c\u5f53\u5b9e\u4f8b<code>\u9075\u5faa<\/code>\u534f\u8bae\u65f6\uff0c\u8fd4\u56de\u8be5\u534f\u8bae\u7c7b\u578b;\u5426\u5219\u8fd4\u56de<code>nil<\/code>\u3002<\/li>\n<li><code>as<\/code>\u7528\u4ee5\u5f3a\u5236\u5411\u4e0b\u8f6c\u578b\uff0c\u5982\u679c\u5f3a\u8f6c\u5931\u8d25\uff0c\u4f1a\u5f15\u8d77\u8fd0\u884c\u65f6\u9519\u8bef\u3002<\/li>\n<\/ul>\n<h3>\u5b9e\u4f8b<\/h3>\n<p>\n\u4e0b\u9762\u7684\u4f8b\u5b50\u5b9a\u4e49\u4e86\u4e00\u4e2a HasArea \u7684\u534f\u8bae\uff0c\u8981\u6c42\u6709\u4e00\u4e2aDouble\u7c7b\u578b\u53ef\u8bfb\u7684 area\uff1a\n<\/p>\n<pre>\nprotocol HasArea {\n    var area: Double { get }\n}\n\n\/\/ \u5b9a\u4e49\u4e86Circle\u7c7b\uff0c\u90fd\u9075\u5faa\u4e86HasArea\u534f\u8bae\nclass Circle: HasArea {\n    let pi = 3.1415927\n    var radius: Double\n    var area: Double { return pi * radius * radius }\n    init(radius: Double) { self.radius = radius }\n}\n\n\/\/ \u5b9a\u4e49\u4e86Country\u7c7b\uff0c\u90fd\u9075\u5faa\u4e86HasArea\u534f\u8bae\nclass Country: HasArea {\n    var area: Double\n    init(area: Double) { self.area = area }\n}\n\n\/\/ Animal\u662f\u4e00\u4e2a\u6ca1\u6709\u5b9e\u73b0HasArea\u534f\u8bae\u7684\u7c7b\nclass Animal {\n    var legs: Int\n    init(legs: Int) { self.legs = legs }\n}\n\nlet objects: [AnyObject] = [\n    Circle(radius: 2.0),\n    Country(area: 243_610),\n    Animal(legs: 4)\n]\n\nfor object in objects {\n    \/\/ \u5bf9\u8fed\u4ee3\u51fa\u7684\u6bcf\u4e00\u4e2a\u5143\u7d20\u8fdb\u884c\u68c0\u67e5\uff0c\u770b\u5b83\u662f\u5426\u9075\u5faa\u4e86HasArea\u534f\u8bae\n    if let objectWithArea = object as? HasArea {\n        print(\"\u9762\u79ef\u4e3a \\(objectWithArea.area)\")\n    } else {\n        print(\"\u6ca1\u6709\u9762\u79ef\")\n    }\n}\n<\/pre>\n<p>\u4ee5\u4e0a\u7a0b\u5e8f\u6267\u884c\u8f93\u51fa\u7ed3\u679c\u4e3a\uff1a<\/p>\n<pre>\n\u9762\u79ef\u4e3a 12.5663708\n\u9762\u79ef\u4e3a 243610.0\n\u6ca1\u6709\u9762\u79ef\n<\/pre>\n<\/p><\/div>\n<\/p><\/div>\n<span>","protected":false},"excerpt":{"rendered":"<p class=\"excerpt\"><span itemprop=\"description\">Swift \u534f\u8bae \u534f\u8bae\u89c4\u5b9a\u4e86\u7528\u6765\u5b9e\u73b0\u67d0\u4e00\u7279\u5b9a\u529f\u80fd\u6240\u5fc5\u9700\u7684\u65b9\u6cd5\u548c\u5c5e\u6027\u3002 \u4efb\u610f\u80fd\u591f\u6ee1\u8db3\u534f\u8bae\u8981\u6c42&hellip;<\/span><\/p>\n<p class=\"more-link-p btn-align-right\"><a class=\"green zoom-btn\" href=\"https:\/\/www.puzi7.net\/?p=548\">Read More<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[26,28],"tags":[74,119],"class_list":["post-548","post","type-post","status-publish","format-standard","hentry","category-mobile","category-swift","tag-ios","tag-swift","zoom-theme-has-thumb"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.3 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Swift \u534f\u8bae - \u8c31\u5b50\u68cb - Puzi7<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.puzi7.net\/?p=548\" \/>\n<meta property=\"og:locale\" content=\"zh_CN\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Swift \u534f\u8bae - \u8c31\u5b50\u68cb - Puzi7\" \/>\n<meta property=\"og:description\" content=\"Swift \u534f\u8bae \u534f\u8bae\u89c4\u5b9a\u4e86\u7528\u6765\u5b9e\u73b0\u67d0\u4e00\u7279\u5b9a\u529f\u80fd\u6240\u5fc5\u9700\u7684\u65b9\u6cd5\u548c\u5c5e\u6027\u3002 \u4efb\u610f\u80fd\u591f\u6ee1\u8db3\u534f\u8bae\u8981\u6c42&hellip;Read More\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.puzi7.net\/?p=548\" \/>\n<meta property=\"og:site_name\" content=\"\u8c31\u5b50\u68cb - Puzi7\" \/>\n<meta property=\"article:published_time\" content=\"2018-02-23T15:39:13+00:00\" \/>\n<meta name=\"author\" content=\"\u77f3\u8863\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"\u4f5c\u8005\" \/>\n\t<meta name=\"twitter:data1\" content=\"\u77f3\u8863\" \/>\n\t<meta name=\"twitter:label2\" content=\"\u9884\u8ba1\u9605\u8bfb\u65f6\u95f4\" \/>\n\t<meta name=\"twitter:data2\" content=\"4 \u5206\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/www.puzi7.net\\\/?p=548#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/www.puzi7.net\\\/?p=548\"},\"author\":{\"name\":\"\u77f3\u8863\",\"@id\":\"https:\\\/\\\/www.puzi7.net\\\/#\\\/schema\\\/person\\\/87dd4941c8ec260c1350b7f41980a190\"},\"headline\":\"Swift \u534f\u8bae\",\"datePublished\":\"2018-02-23T15:39:13+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\\\/\\\/www.puzi7.net\\\/?p=548\"},\"wordCount\":23,\"commentCount\":0,\"keywords\":[\"iOS\",\"Swift\"],\"articleSection\":[\"Mobile\",\"Swift\"],\"inLanguage\":\"zh-Hans\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\\\/\\\/www.puzi7.net\\\/?p=548#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/www.puzi7.net\\\/?p=548\",\"url\":\"https:\\\/\\\/www.puzi7.net\\\/?p=548\",\"name\":\"Swift \u534f\u8bae - 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