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Pure virtual function with implementation

...e type can still define an implementation. A derived class can explicitly call the base class implementation (if access permissions allow it) by using a fully-scoped name (by calling A::f() in your example - if A::f() were public or protected). Something like: class B : public A { virtual voi...
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How can I pretty-print JSON using Go?

...NewFormatter() f.Indent = 4 // Marshall the Colorized JSON s, _ := f.Marshal(obj) fmt.Println(string(s)) } I'm writing the documentation for it now but I was excited to share my solution. share | ...
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Can table columns with a Foreign Key be NULL?

...d Mar 2 '10 at 21:37 Daniel VassalloDaniel Vassallo 301k6666 gold badges475475 silver badges424424 bronze badges ...
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Swift - How to convert String to Double

...ocumentation:(They are not locale-aware) The following convenience methods all skip initial space characters (whitespaceSet) and ignore trailing characters. They are not locale-aware. NSScanner or NSNumberFormatter can be used for more powerful and locale-aware parsing of numbers. ...
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Use of undeclared identifier 'kUTTypeMovie'

... MobileCoreServices Open Video Camera @IBAction func openVideoCamera(_ sender: Any) { if UIImagePickerController.isSourceTypeAvailable(.camera) { let imagePicker = UIImagePickerController() imagePicker.delegate = self imagePicker.sourceType = .camera imageP...
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Get the IP address of the machine

...hould be the same below. I've done a quick example below which will print all of the machine's IPv4 address, (you should also check the getifaddrs was successful ie returns 0). I've updated it show IPv6 addresses too. #include <stdio.h> #include <sys/types.h> #include <ifaddr...
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Sort array of objects by string property value

...ite your own comparison function: function compare( a, b ) { if ( a.last_nom < b.last_nom ){ return -1; } if ( a.last_nom > b.last_nom ){ return 1; } return 0; } objs.sort( compare ); Or inline (c/o Marco Demaio): objs.sort((a,b) => (a.last_nom > b.last_nom) ? 1 :...
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MQTT物联网协议完全实践指南 · App Inventor 2 中文网

...载: de.ullisroboterseite.ursai2pahomqtt.aix 完整示例项目: mqtt_demo.aia MQTT协议深度解析 1. 协议架构与通信模式 MQTT采用客户端-服务器架构,基于发布/订阅(Publish/Subscribe)模式实现消息传递: grap...
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How do I remove/delete a folder that is not empty?

... This doesn't work for me: Traceback (most recent call last): File "foo.py", line 31, in <module> shutil.rmtree(thistestdir) File "/usr/lib/python2.6/shutil.py", line 225, in rmtree onerror(os.rmdir, path, sys.exc_info()) File "/usr/lib/python2.6/shutil.py...
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How to get scrollbar position with Javascript?

...roll position isn't set on document.body in most modern browsers - it's usually set on document.documentElement now. See bugs.chromium.org/p/chromium/issues/detail?id=157855 for Chrome's transition. – fzzfzzfzz May 3 '18 at 15:51 ...