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  • Using scanf() in C++ programs is faster than using cin ?

    - by zeroDivisible
    Hello, I don't know if this is true, but when I was reading FAQ on one of the problem providing sites, I found something, that poke my attention: Check your input/output methods. In C++, using cin and cout is too slow. Use these, and you will guarantee not being able to solve any problem with a decent amount of input or output. Use printf and scanf instead. Can someone please clarify this? Is really using scanf() in C++ programs faster than using cin something ? If yes, that is it a good practice to use it in C++ programs? I thought that it was C specific, though I am just learning C++...

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  • Best approach to creating a database driven Java website?

    - by Craig Whitley
    I'm fairly new to programming and new to java, but I'd like to jump in the deep end with a little database driven website project. I've read quite a lot about requirements in the 'real world' requesting experience with Spring and Hibernate, so I have those installed on netbeans and a project created (if I hit run I get the default spring page). Now I just need a little guidance as to where to start designing my app (please tell me if I'm getting in a bit too over my head for a beginner!). Should I start off with my classes? - create all my classes as they map to my database tables and decide which attributes and methods each will require? Can anyone suggest any good books for maybe.. making a java based website from scratch (i.e. from design right through to deployment) that might be useful for a beginner? Any help appreciated thanks.

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  • I'm having a hard time wrapping my head around handling the Activity Lifecycle...

    - by kefs
    So it seems i've created a fatal flaw and coded an app before understanding/handling rotation/lifecycle events.. Currently, all of my code is in onCreate of each activity. I've read a lot of lifecycle tutorials online, including the official dev guide info, but i'm still having an almost unbelievably hard time trying to wrap my head around the rotation/lifecycle events/methods and when to use them correctly. For example, my app currently has an activity that opens the db, inserts a record, then closes the db.. if i rotate my screen on this activity, the data is re-entered into the db. Using the available lifecycle events (onPause(), onResume(), etc..), how would I prevent this db call from happening again? Would I have to pass a variable through the state saying that the db call has been done, and not to do it again? Thanks in advance..

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  • memory usage in iOS

    - by varun
    My app has a simple UI interface having simple buttons, date picker, picker view, table view, action sheet, toolbar, alert boxes etc. No images, no network access. Just plain simple UI. It accesses SQLite database a lot. ARC option is enabled. I have many questions to ask: In .h files, I am defining IBOutlets like @property(nonatomic, retain) IBOutlet UIButton *bt; Where do i need to do bt=nil? in didReceiveMemoryWarning or viewDidLoad Live Bytes in Instruments tool is 4-5MB. Is it enough or I need to reduce memory usage? If so, how can I do so? Please mention few important points. Also, what all need to be added to the following methods? applicationDidReceiveMemoryWarning UIApplicationDidReceiveMemoryWarningNotification

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  • C++ Multiple Inheritance Question

    - by John
    The scenario generating this is quite complex so I'll strip out a few pieces and give an accurate representation of the classes involved. /* This is inherited using SI by many classes, as normal */ class IBase { virtual string toString()=0; }; /* Base2 can't inherit IBase due to other methods on IBase which aren't appropriate */ class Base2 { string toString() { ... } }; /* a special class, is this valid? */ class Class1 : public IBase, public Base2 { }; So, is this valid? Will there be conflicts on the toString? Or can Class1 use Base2::toString to satisfy IBase? Like I say there are lots of other things not shown, so suggestions for major design changes on this example are probably not that helpful... though any general suggestions/advice are welcome.

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  • What is an Enterprise Java Bean really?

    - by HDave
    On the Tomcat FAQ it says: "Tomcat is not an EJB server. Tomcat is not a full J2EE server." But if I: use Spring to supply an application context annotate my entities with JPA annotations (and use Hibernate as a JPA provider) configure C3P0 as a connection pooling data source annotate my service methods with @Transactional (and use Atomikos as JTA provider) Use JAXB for marshalling and unmarshalling and possibly add my own JNDI capability then don't I effectively have a JEE application server? And then aren't my beans EJBs? Or is there some other defining characteristic? What is it that a JEE compliant app server gives you that you can't easily/readily get from Tomcat with some 3rd party subsystems?

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  • Qt: any way to automatically generate QSharedData-based structures?

    - by Eye of Hell
    Hello. Qt has a build-in supprt for creating objects with integrated reference counting via QSharedData and QSharedDataPointer. All wordks great, but for each such object i need to write a lot of code: QSharedData-based implementation class with constructor and copy constructor, object class itsef with accessor methods for each filed. For a simple structures with 5-10 fields this requires really lot of near same code. Is it some ways to automate such classes generation? Maybe it's some generators exists that take a short description and automatically generates implementation class and object class with all accessors?

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  • Serializing System.Drawing.Color in .NET

    - by alankdkd
    Hi all, I've used the default .NET serialization for a class with a System.Drawing.Color member. The code is now in use by people, and I need to add an extra member to the class, but still deserialize older versions. So I tried the standard way of doing this: The ISerializable interface, using SerializationInfo methods to get the int and string members. The problem: My class also has a System.Drawing.Color member, but SerializationInfo doesn't provide a "GetColor" method read this data type. I've tried getting it as an int and as a string, and casting it to System.Drawing.Color, but no luck. Does anyone know how to deserialize a System.Drawing.Color from SerializationInfo? Thanx! Alan

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  • how to interpret testng console log message for passing tests?

    - by Kunal Cholera
    I ran testng tests for my test classes, I get the following three types of log output when I run the passing tests. I am using org.testng.AssertJUnit.assertTrue() methods in my tests. [testng] PASSED: testMethod1 on null(test.foo.bar.Class1) [testng] PASSED: testMethod2 on Default test name(test.foo.bar.jar.Class2) [testng] PASSED: testMethod3 Can any one please tell me why for some tests it says "on null" for some it says "on Default test name ... " and for some it does not say anything on the console output. Specifically I want to make it consistent message. Environment : linux Testng framework : 6.3.2beta please advise. thanks.

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  • Instantiation vs. Typed reference

    - by Farstucker
    Just when I think Im starting to understand the basics, I find something that brings me right back to reality. In this case, typed reference. I found an example similar to this: class Worker { Boss boss; public void Advise(Boss pBoss) { this.boss = pBoss; } How can you reference methods within the Boss class if its not static and not instantiated? I guess my real question is whats the difference between: Boss boss; and Boss boss = new Boss(); Thank you, FS

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  • Returning EF entities using WCF - Read only web service / public API

    - by alex
    I'm currently migrating an application from Linq-to-SQL & ASP.net Web Services (asmx) to Entity Framework and WCF. My question is, I have a bunch of POCO classes which i have xml mapping files for (for the linq to sql) I've replaced my linq to sql with an entity framework data model I've got an interface - something like IService - that has all the methods on it that i need my service to implement - for example: Product[] GetProductsByKeyword(string keyword); In the above case, Product is a POCO. I now have them as entities within my ef data model - i'm using .net 4, and could take advantage of poco support, but don't really see the need - This service is strictly read only. What's the best way of returning entities in my WCF service? I want it to support other client platforms, not just .net (so php guys could use it)

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  • How to dynamically assign asp.net control ID's

    - by Akk
    I want to do something like the following in an asp.net web form but get a Invalid Token error message: <ul> <%foreach (var item in Items) {%> <li> <asp:TextBox ID="<%= item.Id %>" runat="server" /> </li> <%} %> </ul> What alternative methods are there to achieve the desired result?

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  • Is MDI Form focused?

    - by Vercas
    I've had so much luck developing my application... until now. My application's main form is a MDI parent, and I didn't think of adding any MDI children in my tests until tonight. To my surprise, the MDI parent seems to never "get focus" now. The Focus event and the OnFocus method are never called! I mean... it appears focused but none of the in-code focusing events/methods work. Instead a MDI child reports the focus. How do I fix this?

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  • Is `eval`ing in a CPAN module without localizing $@ a bug?

    - by rassie
    I think I've encountered a bug in Params::Validate, but I'm not sure whether I identified the problematic code piece correctly. The code in question failed to pass exceptions up the chain (using Try::Tiny), so I started debugging and found out that a class used inside the try block has a destructor. This destructor calls object methods which use Params::Validate and looking into Validate.pm source I see an eval without $@ localization, i.e. the global $@ gets overwritten. Now I see two options: Params::Validate should always localize $@ and thus it's a bug that should be reported. The bug is in the class in question, because it shouldn't use Params::Validate in a destructor. Params::Validate can stay as it is now. Which one is it? How I should I handle this situation? PS: I think that CPAN modules should be rock-solid and neither break themselves nor their environment, hence the question title.

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  • Microsoft learning support for VS2010

    - by John
    OK, I am a big fan of WPF, and while it is large area to fully understand, Microsoft has been great in posting loads of training video at http://windowsclient.net/learn/videos_wpf.aspx However with the release of 2010 it all seams to have gone very quiet. I expected a lot of the support to be updated for 2010 and I also expected a lot of new videos on the best way to use the new features in 2010. Currently I find myself working through videos based on 2008 (or even 2005) and trying to apply them to 2010. Don't get me wrong it not that I mind doing this, it just that I fear I may be learning methods which have better or different solutions in 2010. It is just me expecting too much of Microsoft, or have I missed out on a new website?

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  • C# private (hidden) base class

    - by Loadmaster
    It is possible to make a C# base class accessible only within the library assembly it's compiled into, while making other subclasses that inherit from it public? For example: using System.IO; class BaseOutput: Stream // Hidden base class { protected BaseOutput(Stream o) { ... } ...lots of common methods... } public class MyOutput: BaseOutput // Public subclass { public BaseOutput(Stream o): base(o) { ... } public override int Write(int b) { ... } } Here I'd like the BaseOutput class to be inaccessible to clients of my library, but allow the subclass MyOutput to be completely public. I know that C# does not allow base classes to have more restrictive access than subclasses, but is there some other legal way of achieving the same effect?

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  • How to load an entity by a key other than primary key?

    - by stacker
    In a customized servlet (seam 2.1.2) this works fine TableNameHome tableNameHome = (TableNameHome) Component.getInstance( "tableNameHome " ); tableName entity = tableNameHome.getInstance(); entity.setXXX(); tableNameHome.persit(); However this one fails: entityManager = tableNameHome .getEntityManager(); Query query = entityManager.createQuery( "SELECT b FROM tablename b WHERE b.box_id = :key2nd" ); query.setParameter( "key2nd", value); List results = query.getResultList(); and leads to this error message: org.hibernate.hql.ast.QuerySyntaxException: tablename is not mapped [SELECT b FROM tablename b WHERE b.key2nd = :key2nd] In EJB 2.1 I could implement other finder-methods. EntityHome.find() searches only by primary key. What do I need to do in order to query by a different criteria than primary key?

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  • Junit 4 test suite and individual test classes

    - by Hypnus
    I have a JUnit 4 test suite with BeforeClass and AfterClass methods that make a setup/teardown for the following test classes. What I need is to run the test classes also by them selves, but for that I need a setup/teardown scenario (BeforeClass and AfterClass or something like that) for each test class. The thing is that when I run the suite I do not want to execute the setup/teardown before and after each test class, I only want to execute the setup/teardown from the test suite (once). Is it possible ? Thanks in advance.

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  • Tracing all events in VB.NET

    - by MatsT
    I keep running into situations where I don't know what event I have to listen to in order to execute my code at the correct time. Is there any way to get a log of all events that is raised? Any way to filter that log based on what object raised the event? EDIT: Final solution: Private Sub WireAllEvents(ByVal obj As Object) Dim parameterTypes() As Type = {GetType(System.Object), GetType(System.EventArgs)} Dim Events = obj.GetType().GetEvents() For Each ev In Events Dim handler As New DynamicMethod("", Nothing, parameterTypes, GetType(main)) Dim ilgen As ILGenerator = handler.GetILGenerator() ilgen.EmitWriteLine("Event Name: " + ev.Name) ilgen.Emit(OpCodes.Ret) ev.AddEventHandler(obj, handler.CreateDelegate(ev.EventHandlerType)) Next End Sub And yes, I know this is not a good solution when you actually want to do real stuff that triggers off the events. There are good reasons for the 1 method - 1 event approach, but this is still useful when trying to figure out which of the methods you want to add your handlers to.

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  • Android how to call a method of MainActivity in SmsReceiver Class

    - by GeneticSmart
    I'm very new to Android Programming, It would be really great if someone can help me in this.My project contains two JAVA files. MainActivity.java extends Activity SMSReceiver.java extends Broadcastreceiver The SMSreceiver.java has the code which displays any incoming SMS in toast. Can you please tell me how to call a function in MainActivity whenever a particular SMS is received. For eg: when I receive sms called as starttemp it should call a function starttemp. I have searched a lot and found that intents are a way to do this and we cannot call these methods directly. Please can anyone help me in this? And it would be really great if someone can send me working code.

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  • Apache2 on Ubuntu Server w/ CGI, FastCGI, mod_php

    - by illegal3alien
    I've looked at various websites on configuring Apache with cgi and can't get mod_fcgid to work. It works fine using mod_php5, but I wanted to compare performance using cgi and fastcgi. I tried methods using FGCIWrapper among various other techniques and the only one that didn't result in an unlogged 403 or download of the file was using "Action application/x-httpd-php /usr/bin/php-cgi" When trying to configure mod_fcgid the file normally just started a download of an unprocessed file. I used wget to check headers and type was "application/x-httpd-php" At one point I was able to get to the page, but it resulted in a 403, which was listed in access.log, but not error.log (I was told it should be in there too) I tried to get it working on a fresh install of Ubuntu Server 10.04 LTS and 10.10 and had the same results on both, so I'm not doing something correctly in terms of configuration. I tried virtualmin and could only get mod_php to work. The page just prompted a download when selecting cgi or fcgi from the control panel.

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  • [C#] How to share a variable between two classes?

    - by Altefquatre
    Hello, How would you share the same object between two other objects? For instance, I'd like something in that flavor: class A { private string foo_; // It could be any other class/struct too (Vector3, Matrix...) public A (string shared) { this.foo_ = shared; } public void Bar() { this.foo_ = "changed"; } } ... // inside main string str = "test"; A a = new A(str); Console.WriteLine(str); // "test" a.Bar(); Console.WriteLine(str); // I get "test" instead of "changed"... :( I read there is some ref/out stuff, but I couldn't get what I'm asking here. I could only apply some changes in the methods scope where I was using ref/out arguments... I also read we could use pointers, but is there no other way to do it? Thanks Altefquatre

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  • In OCaml, how can I create an out_channel which writes to a string/buffer instead of a file on disk

    - by Tianyi Cui
    I have a function of type in_channel -> out_channel -> unit which will output something to an out_channel. Now I'd like to get its output as a string. Creating temporary files to write and read it back seems ugly, so how can I do that? Is there any other methods to create out_channel besides Pervasives.open_out family? Actually, this function implemented a repl. What I really need is to test it programmatically, so I'd like to first wrap it to a function of type string -> string. For creating the in_channel, it seems I can use Scanf.Scanning.from_string, but I don't know how to create the out_channel parameter.

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  • How can an SQL query return data from multiple tables

    - by Fluffeh
    I would like to know how to get data from multiple tables in my database, what types of methods are there to do this, what are joins and unions and how are they different from one another? When should I use each one compared to the others? I am planning to use this in my (for example - PHP) application, but don't want to run multiple queries against the database, what options do I have to get data from multiple tables in a single query? Note: I am writing this as I would like to be able to link to a well written guide on the numerous questions that I constantly come across in the PHP queue, so I can link to this for further detail when I post an answer. The answers cover off the following: Part 1 - Joins and Unions Part 2 - Subqueries Part 3 - Tricks and Efficient Code

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  • Could not able to register the third party DLL using regsvr32

    - by Mahadev Malkar
    i have been trying to register the third party dll file using the regsvr32 command, but it keeps giving me the error that 'the dll doesn't have a entry point, dll could not be registered'. Is it possible to register the dll and use it as a COM component in .NET ? Or I want to use that dll as a COM component in c#.NET. Is there any way to use that dll as COM Component. When i tried to use it as COM component, the dll file, its methods, interfaces are visible in .NET. but when i tried to use any of that interface it gives me error as 'Retrieving the COM class factory for component with CLSID {C4CC4F47-2AF6-41FA-A43D-01E8B3050D3F} failed due to the following error: 80040154.'. Plz tell me any solution.

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