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  • I need to stop execution during recursive algorithm

    - by Shaza
    Hey, I have a problem in choosing the right method to accomplish my goal. I'm working on Algorithms teaching system, I'm using C#. I need to divide my algorithm into steps, each step will contain a recursion. I have to stop execution after each step, user can then move to the next step(next recursion) using a button in my GUI. After searching, threads was the right choice, but I found several methods: (Thread.sleep/interrupt): didn't work, my GUI freezed !! (Suspend/Resume): I've read that it's a bad idea to use. (Waithandles): still reading about them. (Monitor wait/resume). I don't have much time to try and read all previous methods, please help me in choosing the best method that fits my system.Any suggestions are extremal welcomed.

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  • In Java it seems Public constructors are always a bad coding practice

    - by Adam Gent
    This maybe a controversial question and may not be suited for this forum (so I will not be insulted if you choose to close this question). It seems given the current capabilities of Java there is no reason to make constructors public ... ever. Friendly, private, protected are OK but public no. It seems that its almost always a better idea to provide a public static method for creating objects. Every Java Bean serialization technology (JAXB, Jackson, Spring etc...) can call a protected or private no-arg constructor. My questions are: I have never seen this practice decreed or written down anywhere? Maybe Bloch mentions it but I don't own is book. Is there a use case other than perhaps not being super DRY that I missed? EDIT: I explain why static methods are better. .1. For one you get better type inference. For example See Guava's http://code.google.com/p/guava-libraries/wiki/CollectionUtilitiesExplained .2. As a designer of the class you can later change what is returned with a static method. .3. Dealing with constructor inheritance is painful especially if you have to pre-calculate something.

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  • ORM framework that extends base class with database-implementation.

    - by aioobe
    I have a game consisting of a client / server + a webpage. A central notion in both client and game-/webserver is an Account. Accounts are stored in a database thus I'm in need of some ORM and recently had a look at Hibernate and Cayenne. My understanding however, is that both frameworks provide an "DatabaseBackedAccount"-class which I extend with my other Account methods. My problem is that the Account class is reused heavily on the client side, and I would obviously not want to include database-related code on the client implementation. My current solution is to have an Account class (shared by server and client) and extend this with a DatabaseBackedAccount (overriding setter-methods and providing a commit method) on the server side. I find this quite natural and nice, however I've had to implement all gory sql-details and ORM myself. Is there any way to "turn the table" in any existing ORM framework, so that the generated classes extend my existing class?

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  • Incongruity between Eclipse Outline/Package perspective and source code being displayed - Java error generated at runtime

    - by David Daedalus
    I've been debugging a Java application and have encountered something odd. When a particular method is called, Java throws a ClassNotFoundException. Unfortunately, the methods in question (the invoking and the 'missing' one) are inside a JAR file for which I have no documentation or source. To get at the source, I used JD-GUI (a Java JAR reverse engineer-er) and the JD plugin for Eclipse. As far as I can tell, the class in question exists inside the JAR file. This because JD-GUI displays it inside the JAR, and from within Eclipse I can see it listed along with the constructors and methods. My question is why the source being displayed in Eclipse is for a different class (that also exists)? This program was built with Ant - is it possible the problem lies there? Screenshot below for your viewing pleasure - and thanks in advance for your help!

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  • AJAX Issue, Works in all browsers except IE

    - by Nik
    Alright, this code works in Chrome and FF, but not IE (which is to be expected). Does anyone see anything wrong with this code that would render it useless in IE? var waittime=400; chatmsg = document.getElementById("chatmsg"); room = document.getElementById("roomid").value; sessid = document.getElementById("sessid").value; chatmsg.focus() document.getElementById("chatwindow").innerHTML = "loading..."; document.getElementById("userwindow").innerHTML = "Loading User List..."; var xmlhttp = false; var xmlhttp2 = false; var xmlhttp3 = false; function ajax_read() { if(window.XMLHttpRequest){ xmlhttp=new XMLHttpRequest(); if(xmlhttp.overrideMimeType){ xmlhttp.overrideMimeType('text/xml'); } } else if(window.ActiveXObject){ try{ xmlhttp=new ActiveXObject("Msxml2.XMLHTTP"); } catch(e) { try{ xmlhttp=new ActiveXObject("Microsoft.XMLHTTP"); } catch(e){ } } } if(!xmlhttp) { alert('Giving up :( Cannot create an XMLHTTP instance'); return false; } xmlhttp.onreadystatechange = function() { if (xmlhttp.readyState==4) { document.getElementById("chatwindow").innerHTML = xmlhttp.responseText; setTimeout("ajax_read()", waittime); } } xmlhttp.open('GET','methods.php?method=r&room=' + room +'',true); xmlhttp.send(null); } function user_read() { if(window.XMLHttpRequest){ xmlhttp3=new XMLHttpRequest(); if(xmlhttp3.overrideMimeType){ xmlhttp3.overrideMimeType('text/xml'); } } else if(window.ActiveXObject){ try{ xmlhttp3=new ActiveXObject("Msxml2.XMLHTTP"); } catch(e) { try{ xmlhttp3=new ActiveXObject("Microsoft.XMLHTTP"); } catch(e){ } } } if(!xmlhttp3) { alert('Giving up :( Cannot create an XMLHTTP instance'); return false; } xmlhttp3.onreadystatechange = function() { if (xmlhttp3.readyState==4) { document.getElementById("userwindow").innerHTML = xmlhttp3.responseText; setTimeout("user_read()", 10000); } } xmlhttp3.open('GET','methods.php?method=u&room=' + room +'',true); xmlhttp3.send(null); } function ajax_write(url){ if(window.XMLHttpRequest){ xmlhttp2=new XMLHttpRequest(); if(xmlhttp2.overrideMimeType){ xmlhttp2.overrideMimeType('text/xml'); } } else if(window.ActiveXObject){ try{ xmlhttp2=new ActiveXObject("Msxml2.XMLHTTP"); } catch(e) { try{ xmlhttp2=new ActiveXObject("Microsoft.XMLHTTP"); } catch(e){ } } } if(!xmlhttp2) { alert('Giving up :( Cannot create an XMLHTTP instance'); return false; } xmlhttp2.open('GET',url,true); xmlhttp2.send(null); } function submit_msg(){ nick = document.getElementById("chatnick").value; msg = document.getElementById("chatmsg").value; document.getElementById("chatmsg").value = ""; ajax_write("methods.php?method=w&m=" + msg + "&n=" + nick + "&room=" + room + "&sessid=" + sessid + ""); } function keyup(arg1) { if (arg1 == 13) submit_msg(); } var intUpdate = setTimeout("ajax_read()", waittime); var intUpdate = setTimeout("user_read()", 0);

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  • C++ method declaration, class definition problem

    - by John Fra.
    I have 2 classes: A and B. Some methods of class A need to use class B and the opposite(class B has methods that need to use class A). So I have: class A; class B { method1(A a) { } } class A { method1(B b) { } void foo() { } } and everything works fine. But when I try to call foo() of class A from B::method1 like this: class B { method1(A a) { a.foo(); } } I get as result compile errors of forward declaration and use of incomplete type. But why is this happening? (I have declared class A before using it?)

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  • AJAX with Ruby on Rails?

    - by Zachary
    This is probably a really dumb question with a simple answer but... I am working on a project where I need to use AJAX to send/receive information. I am using Ruby on Rails (which I am pretty new to), but rather than using the helper methods or the built in functionality in the 'defaults' Javascript file, I need to do this manually in my own Javascript. I believe that ultimately I will want to send a request with a JSON object, then have the controller return another JSON object containing the requested information. The problem is that I cannot seem to find the syntax for sending something to a specific controller method, with parameters, directly from Javascript - everything I Google ends up being tutorials for using the Rails AJAX helper methods.

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  • Ruby on Rails: attr_accessor for submodels

    - by williamjones
    I'm working with some models where a lot of a given model's key attributes are actually stored in a submodel. Example: class WikiArticle has_many :revisions has_one :current_revision, :class_name => "Revision", :order => "created_at DESC" end class Revision has_one :wiki_article end The Revision class has a ton of database fields, and the WikiArticle has very few. However, I often have to access a Revision's fields from the context of a WikiArticle. The most important case of this is probably on creating an article. I've been doing that with lots of methods that look like this, one for each field: def description if @description @description elsif current_revision current_revision.description else "" end end def description=(string) @description = string end And then on my save, I save @description into a new revision. This whole thing reminds me a lot of attr_accessor, only it doesn't seem like I can get attr_accessor to do what I need. How can I define an attr_submodel_accessor such that I could just give field names and have it automatically create all those methods the way attr_accessor does?

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  • Solutions for redundant server and client code?

    - by Fragsworth
    In our system, the code which exists on the client side (in Flash and Javascript) mirrors the code that exists on the server side (e.g. in Python or PHP), normally with respect to the models, the methods available for those models, and the unit tests written for them. This becomes a problem in systems where you want to minimize data transfer (e.g. multiplayer games). I do not want to write the same code and unit tests redundantly for both the client and server, but I don't know of any standard solutions to deal with this. Basically, I want a language/compiler which can produce models and methods for three main languages: Actionscript, Javascript, and any server language. Does something like this exist?

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  • Preventing Netbeans JAXB generation trashing classes

    - by Mac
    I'm developing a SOAP service using JAX-WS and JAXB under Netbeans 6.8, and getting a little frustrated with Netbeans trashing my work every time the XSD schema my JAXB bindings are based upon changes. To elaborate, the IDE automatically generates classes bound to the schema, which can then be (un)marshalled from/to XML using JAXB. To these classes I've added extra methods to (for example) convert to and from separate classes designed to be persisted to database with JPA. The problem is that whenever the schema changes and I rebuild, these classes are regenerated, and all my custom methods are deleted. I can manually replace them by copy-pasting from a backup file, but that is rather time-consuming and tedious. As I'm using an iterative design approach, the schema is changing rather frequently and I'm wasting an awful lot of time whenever it does, simply to reinstate my previous code. While the IDE automatically regenerating the JAXB-bound classes is entirely reasonable and I don't mean to imply otherwise, I was wondering if anyone had any bright ideas as to how to prevent my extra work having to be manually reinstated every time my schema changes?

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  • Multiple SessionFactories in Windows Service with NHibernate

    - by Rob Taylor
    Hi all, I have a Webapp which connects to 2 DBs (one core, the other is a logging DB). I must now create a Windows service which will use the same business logic/Data access DLLs. However when I try to reference 2 session factories in the Service App and call the factory.GetCurrentSession() method, I get the error message "No session bound to current context". Does anyone have a suggestion about how this can be done? public class StaticSessionManager { public static readonly ISessionFactory SessionFactory; public static readonly ISessionFactory LoggingSessionFactory; static StaticSessionManager() { string fileName = System.Configuration.ConfigurationSettings.AppSettings["DefaultNHihbernateConfigFile"]; string executingPath = System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().GetName().CodeBase); fileName = executingPath + "\\" + fileName; SessionFactory = cfg.Configure(fileName).BuildSessionFactory(); cfg = new Configuration(); fileName = System.Configuration.ConfigurationSettings.AppSettings["LoggingNHihbernateConfigFile"]; fileName = executingPath + "\\" + fileName; LoggingSessionFactory = cfg.Configure(fileName).BuildSessionFactory(); } } The configuration file has the setting: <property name="current_session_context_class">call</property> The service sets up the factories: private ISession _session = null; private ISession _loggingSession = null; private ISessionFactory _sessionFactory = StaticSessionManager.SessionFactory; private ISessionFactory _loggingSessionFactory = StaticSessionManager.LoggingSessionFactory; ... _sessionFactory = StaticSessionManager.SessionFactory; _loggingSessionFactory = StaticSessionManager.LoggingSessionFactory; _session = _sessionFactory.OpenSession(); NHibernate.Context.CurrentSessionContext.Bind(_session); _loggingSession = _loggingSessionFactory.OpenSession(); NHibernate.Context.CurrentSessionContext.Bind(_loggingSession); So finally, I try to call the correct factory by: ISession session = StaticSessionManager.SessionFactory.GetCurrentSession(); Can anyone suggest a better way to handle this? Thanks in advance! Rob

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  • Getting two variables in the URL with htaccess

    - by Wayne
    What way it is to be to get two GET methods in the URL by htaccess? RewriteRule ^adm/(.*)$ adm.php?mode=$1 I've used that for the example URL: http://www.domain.com/adm/thismode Now I want to get two methods like: http://www.domain.com/adm/thismode/othermode I've tried this: RewriteRule ^adm/(.*)$/(.*)$ adm.php?mode=$1&othermode=$2 But doesn't seem to work... how do I get it to do that? EDIT: $mode1 = $_GET['mode']; $mode2 = $_GET['othermode']; Like this...

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  • How to combine multiple uiBinder-based widgets?

    - by jprusakova
    I need to insert a [number of] uiBinder-based widgets into another one, at a particular spot. The inserted widget has a somewhat complicated layout, so I am trying to define it in HTML. referencePanel.add(...) fails with NoSuchElement exception. reference.getElement().toSource returns "undefined". Any suggestions on how to do that? public class AppUIDemo extends Composite { @UiTemplate("AppUIDemo.ui.xml") interface AppUIDemoUiBinder extends UiBinder<Widget, AppUIDemo> { } @UiTemplate("ReferenceUI.ui.xml") interface ReferenceUIUiBinder extends UiBinder<Widget, ReferenceUI> { } private static AppUIDemoUiBinder uiBinder = GWT .create(AppUIDemoUiBinder.class); private static ReferenceUIUiBinder refUIBinder = GWT .create(ReferenceUIUiBinder.class); @UiField HTMLPanel referencePanel; public AppUIDemo() { initWidget(uiBinder.createAndBindUi(this)); ReferenceUI reference = new ReferenceUI(refUIBinder); referencePanel.add(reference, reference.getElement().getId()); } } public class ReferenceUI extends Composite { interface ReferenceUIUiBinder extends UiBinder<Widget,ReferenceUI> { } private static ReferenceUIUiBinder uiBinder = GWT .create(ReferenceUIUiBinder.class); public ReferenceUI() { initWidget(uiBinder.createAndBindUi(this)); } public CreditReferenceUI(final UiBinder<Widget, CreditReferenceUI> binder) { initWidget(binder.createAndBindUi(this)); } }

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  • WCF RIA Services v1.0 Timeouts

    - by Dan Wray
    I have a RIA service methods which return quite a large amount of (binary) data to my silverlight application. The methods themselves (database access etc) complete quickly, but since I upgraded to v1.0 from the RC2 I've been experiencing timeouts, even when I limit the data returned to the smallest objects. Debug shows the method returning, then 20-30 seconds later the silverlight "method complete" event will fire. There is not enough data to cause that much lag. Could anyone suggest why this might be? I've been unable to find any breaking changes documentation specific to the RC2 = 1.0 upgrade. Trying to eliminate any other possible causes also, but this is literally a case of worked before the install, doesn't work now! (also upgraded silverlight 4 tools for vs).

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  • Should I use custom exceptions to control the flow of application?

    - by bonefisher
    Is it a good practise to use custom business exceptions (e.g. BusinessRuleViolationException) to control the flow of user-errors/user-incorrect-inputs??? The classic approach: I have a web service, where I have 2 methods, one is the 'checker' (UsernameAlreadyExists()) and the other one is 'creator' (CreateUsername())... So if I want to create a username, I have to do 2 roundtrips to webservice, 1.check, 2.if check is OK, create. What about using UsernameAlreadyExistsException? So I call only the 2. web service method (CrateUsername()), which contains the check and if not successfull, it throws the UsernameAlreadyExistsException. So the end goal is to have only one round trip to web service and the checking can be contained also in other web service methods (so I avoid calling the UsernameAlreadyExists() all the times..). Furthermore I can use this kind of business error handling with other web service calls completely avoiding the checking prior the call.

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  • Tower of Hanoi, stop sliding

    - by ArtWorkAD
    Hi, I developed a solution for the Tower of Hanoi problem: public static void bewege(int h, char quelle, char ablage, char ziel) { if(h > 0){ bewege(h - 1, quelle, ziel, ablage); System.out.println("Move "+ h +" from " + quelle + " to " + ziel); bewege(h - 1, ablage, quelle, ziel); } } It works fine. Now i want to limit the number of slides and throw an exception if a certain limit is reached. I tried it with a counter but it does not work: class HanoiNK{ public static void main(String args[]){ Integer n = Integer.parseInt(args[0]); Integer k = Integer.parseInt(args[1]); try{ bewege(k, n, 'A', 'B', 'C'); }catch(Exception e){ System.out.println(e); } } public static void bewege(int c, int h, char quelle, char ablage, char ziel) throws Exception{ if(h > 0){ if(counter != 0){ bewege(c, h - 1, quelle, ziel, ablage); c--; System.out.println("Move "+ h +" from " + quelle + " to " + ziel); bewege(c, h - 1, ablage, quelle, ziel); c--; }else{ throw new Exception("stop sliding"); } } } } The exception is never thrown. Any ideas?

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  • C# method generic params parameter bug?

    - by Mike M
    Hey, I appears to me as though there is a bug/inconsistency in the C# compiler. This works fine (first method gets called): public void SomeMethod(string message, object data); public void SomeMethod(string message, params object[] data); // .... SomeMethod("woohoo", item); Yet this causes "The call is ambiguous between the following methods" error: public void SomeMethod(string message, T data); public void SomeMethod(string message, params T[] data); // .... SomeMethod("woohoo", (T)item); I could just use the dump the first method entirely, but since this is a very performance sensitive library and the first method will be used about 75% of the time, I would rather not always wrap things in an array and instantiate an iterator to go over a foreach if there is only one item. Splitting into different named methods would be messy at best IMO. Thoughts?

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  • AudioRecord problems with non-HTC devices

    - by Marc
    I'm having troubles using AudioRecord. An example using some of the code derived from the splmeter project: private static final int FREQUENCY = 8000; private static final int CHANNEL = AudioFormat.CHANNEL_CONFIGURATION_MONO; private static final int ENCODING = AudioFormat.ENCODING_PCM_16BIT; private int BUFFSIZE = 50; private AudioRecord recordInstance = null; ... android.os.Process.setThreadPriority(android.os.Process.THREAD_PRIORITY_URGENT_AUDIO); recordInstance = new AudioRecord(MediaRecorder.AudioSource.MIC, FREQUENCY, CHANNEL, ENCODING, 8000); recordInstance.startRecording(); short[] tempBuffer = new short[BUFFSIZE]; int retval = 0; while (this.isRunning) { for (int i = 0; i < BUFFSIZE - 1; i++) { tempBuffer[i] = 0; } retval = recordInstance.read(tempBuffer, 0, BUFFSIZE); ... // process the data } This works on the HTC Dream and the HTC Magic perfectly without any log warnings/errors, but causes problems on the emulators and Nexus One device. On the Nexus one, it simply never returns useful data. I cannot provide any other useful information as I'm having a remote friend do the testing. On the emulators (Android 1.5, 2.1 and 2.2), I get weird errors from the AudioFlinger and Buffer overflows with the AudioRecordThread. I also get a major slowdown in UI responsiveness (even though the recording takes place in a separate thread than the UI). Is there something apparent that I'm doing incorrectly? Do I have to do anything special for the Nexus One hardware?

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  • Very strange Application.ThreadException behaviour.

    - by Brann
    I'm using the Application.ThreadException event to handle and log unexpected exceptions in my winforms application. Now, somewhere in my application, I've got the following code (or rather something equivalent, but this dummy code is enough to reproduce my issue) : try { throw new NullReferenceException("test"); } catch (Exception ex) { throw new Exception("test2", ex); } I'm clearly expecting my Application_ThreadException handler to be passed the "test2" exception, but this is not always the case. Typically, if another thread marshals my code to the UI, my handler receives the "test" exception, exactly as if I hadn't caught "test" at all. Here is a short sample reproducing this behavior. I have omitted the designer's code. static class Program { [STAThread] static void Main() { Application.ThreadException += new System.Threading.ThreadExceptionEventHandler(Application_ThreadException); Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); Application.Run(new Form1()); } static void Application_ThreadException(object sender, System.Threading.ThreadExceptionEventArgs e) { Console.WriteLine(e.Exception.Message); } } public partial class Form1 : Form { public Form1() { InitializeComponent(); button1.Click+=new EventHandler(button1_Click); System.Threading.Thread t = new System.Threading.Thread(new System.Threading.ThreadStart(ThrowEx)); t.Start(); } private void button1_Click(object sender, EventArgs e) { try { throw new NullReferenceException("test"); } catch (Exception ex) { throw new Exception("test2", ex); } } void ThrowEx() { this.BeginInvoke(new EventHandler(button1_Click)); } } The output of this program on my computer is : test ... here I click button1 test2 I've reproduced this on .net 2.0,3.5 and 4.0. Does someone have a logical explanation ?

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  • Jpa subclass mapping

    - by Roy Chan
    I am making a POS like system. I wonder how to map subclass using JPA (this is for my DAO). Product class has product details and OrderProduct class has information about the Product and details about the order. @Entity @Table(name="products") public class Product implements Serializable{ @Id @Column(name="id") @GeneratedValue(strategy = GenerationType.AUTO public int getId(){ return id;} /** Other get/set methods */ } @Entity @Table(name="order_products") public class OrderProduct extends Product{ @Id @Column(name="id") @GeneratedValue(strategy = GenerationType.AUTO) public int getId(){ return id;} /** Other get/set methods */ } I got complain about duplicate @Id. But OrderProduct class really need another id than the product one. How should I map this? DB is something like this Table products id int name varchar(32) Table order_product id int quantity int productid int fk referencing product table Would @IdClass or @AttributeOverride help?

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  • Where to learn about VS debugger 'magic names'

    - by Gael Fraiteur
    If you've ever used Reflector, you probably noticed that the C# compiler generates types, methods, fields, and local variables, that deserve 'special' display by the debugger. For instance, local variables beginning with 'CS$' are not displayed to the user. There are other special naming conventions for closure types of anonymous methods, backing fields of automatic properties, and so on. My question: where to learn about these naming conventions? Does anyone know about some documentation? My objective is to make PostSharp 2.0 use the same conventions. Thank you!

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  • Assign C++ instance method to a global-function-pointer ?

    - by umanga
    Greetings, My project structure is as follows: \- base (C static library) callbacks.h callbacks.c paint_node.c . . * libBase.a \-app (C++ application) main.cpp In C library 'base' , I have declared global-function-pointer as: in singleheader file callbacks.h #ifndef CALLBACKS_H_ #define CALLBACKS_H_ extern void (*putPixelCallBack)(); extern void (*putImageCallBack)(); #endif /* CALLBACKS_H_ */ in single C file they are initialized as callbacks.c #include "callbacks.h" void (*putPixelCallBack)(); void (*putImageCallBack)(); Other C files access this callback-functions as: paint_node.c #include "callbacks.h" void paint_node(node *node,int index){ //Call callbackfunction . . putPixelCallBack(node->x,node->y,index); } I compile these C files and generate a static library 'libBase.a' Then in C++ application, I want to assign C++ instance method to this global function-pointer: I did something like follows : in Sacm.cpp file #include "Sacm.h" extern void (*putPixelCallBack)(); extern void (*putImageCallBack)(); void Sacm::doDetection() { putPixelCallBack=(void(*)())&paintPixel; //call somefunctions in 'libBase' C library } void Sacm::paintPixel(int x,int y,int index) { qpainter.begin(this); qpainter.drawPoint(x,y); qpainter.end(); } But when compiling it gives the error: sacmtest.cpp: In member function ‘void Sacm::doDetection()’: sacmtest.cpp:113: error: ISO C++ forbids taking the address of an unqualified or parenthesized non-static member function to form a pointer to member function. Say ‘&Sacm::paintPixel’ sacmtest.cpp:113: error: converting from ‘void (Sacm::)(int, int, int)’ to ‘void ()()’ Any tips?

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  • Type result with Ternary operator in C#

    - by Vaccano
    I am trying to use the ternary operator, but I am getting hung up on the type it thinks the result should be. Below is an example that I have contrived to show the issue I am having: class Program { public static void OutputDateTime(DateTime? datetime) { Console.WriteLine(datetime); } public static bool IsDateTimeHappy(DateTime datetime) { if (DateTime.Compare(datetime, DateTime.Parse("1/1")) == 0) return true; return false; } static void Main(string[] args) { DateTime myDateTime = DateTime.Now; OutputDateTime(IsDateTimeHappy(myDateTime) ? null : myDateTime); Console.ReadLine(); ^ } | } | // This line has the compile issue ---------------+ On the line indicated above, I get the following compile error: Type of conditional expression cannot be determined because there is no implicit conversion between '< null ' and 'System.DateTime' I am confused because the parameter is a nullable type (DateTime?). Why does it need to convert at all? If it is null then use that, if it is a date time then use that. I was under the impression that: condition ? first_expression : second_expression; was the same as: if (condition) first_expression; else second_expression; Clearly this is not the case. What is the reasoning behind this? (NOTE: I know that if I make "myDateTime" a nullable DateTime then it will work. But why does it need it? As I stated earlier this is a contrived example. In my real example "myDateTime" is a data mapped value that cannot be made nullable.)

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  • Is it appropriate to set a value to a "const char *" in the header file

    - by sud
    I have seen people using 2 methods to declare and define char * Medhod-1: The header file has the below const char* COUNTRY_NAME_USA = "USA"; Medhod-2: The header file has the below declaration const char* COUNTRY_NAME_USA; The cpp file has the below defintion : const char* COUNTRY_NAME_USA = "USA"; Is method-2 wrong in some way ? What is the difference between the two ? I understand the difference between "const char * const var" , and "const char * var". If in the above methods if a "const char * const var" is declared and defined in the header as in method 1 will it make sense ?

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