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  • Populating and Using Dynamic Classes in C#/.NET 4.0

    - by Bob
    In our application we're considering using dynamically generated classes to hold a lot of our data. The reason for doing this is that we have customers with tables that have different structures. So you could have a customer table called "DOG" (just making this up) that contains the columns "DOGID", "DOGNAME", "DOGTYPE", etc. Customer #2 could have the same table "DOG" with the columns "DOGID", "DOG_FIRST_NAME", "DOG_LAST_NAME", "DOG_BREED", and so on. We can't create classes for these at compile time as the customer can change the table schema at any time. At the moment I have code that can generate a "DOG" class at run-time using reflection. What I'm trying to figure out is how to populate this class from a DataTable (or some other .NET mechanism) without extreme performance penalties. We have one table that contains ~20 columns and ~50k rows. Doing a foreach over all of the rows and columns to create the collection take about 1 minute, which is a little too long. Am I trying to come up with a solution that's too complex or am I on the right track? Has anyone else experienced a problem like this? Create dynamic classes was the solution that a developer at Microsoft proposed. If we can just populate this collection and use it efficiently I think it could work.

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  • How to use boost::transform_iterator to iterate over modifed std::map values?

    - by Frank
    I have an std::map, and I would like to define an iterator that returns modified values. Typically, a std::map<int,double>::iterator iterates over std::pair<int,double>, and I would like the same behavior, just the double value is multiplied by a constant. I tried it with boost::transform_iterator, but it doesn't compile: #include <map> #include <boost/iterator/transform_iterator.hpp> #include <boost/functional.hpp> typedef std::map<int,double> Map; Map m; m[100] = 2.24; typedef boost::binder2nd< std::multiplies<double> > Function; typedef boost::transform_iterator<Function, Map::value_type*> MultiplyIter; MultiplyIter begin = boost::make_transform_iterator(m.begin(), Function(std::multiplies<double>(), 4)); // now want to similarly create an end iterator // and then iterate over the modified map The error is: error: conversion from 'boost ::transform_iterator< boost::binder2nd<multiplies<double> >, gen_map<int, double>::iterator , boost::use_default, boost::use_default >' to non-scalar type 'boost::transform_iterator< boost::binder2nd<multiplies<double> >, pair<const int, double> * , boost::use_default, boost::use_default >' requested What is gen_map and do I really need it? I adapted the transform_iterator tutorial code from here to write this code ...

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  • question about mergesort

    - by davit-datuashvili
    i have write code on mergesort here is code public class mergesort{ public static int a[]; public static void merges(int work[],int low,int high){ if (low==high) return ; else{ int mid=(low+high)/2; merges(work,low,mid); merges(work,mid+1,high); merge(work,low,mid+1,high); } } public static void main(String[]args){ int a[]=new int[]{64,21,33,70,12,85,44,99,36,108}; merges(a,0,a.length-1); for (int i=0;i<a.length;i++){ System.out.println(a[i]); } } public static void merge(int work[],int low,int high,int upper){ int j=0; int l=low; int mid=high-1; int n=upper-l+1; while(low<=mid && high<=upper) if ( a[low]<a[high]) work[j++]=a[low++]; else work[j++]=a[high++]; while(low<=mid) work[j++]=a[low++]; while(high<=upper) work[j++]=a[high++]; for (j=0;j<n;j++) a[l+j]=work[j]; } } but it does nort work after compile this code here is mistake java.lang.NullPointerException at mergesort.merge(mergesort.java:45) at mergesort.merges(mergesort.java:12) at mergesort.merges(mergesort.java:10) at mergesort.merges(mergesort.java:10) at mergesort.merges(mergesort.java:10) at mergesort.main(mergesort.java:27)

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  • What C++ templates issue is going on with this error?

    - by WilliamKF
    Running gcc v3.4.6 on the Botan v1.8.8 I get the following compile time error building my application after successfully building Botan and running its self test: ../../src/Botan-1.8.8/build/include/botan/secmem.h: In member function `Botan::MemoryVector<T>& Botan::MemoryVector<T>::operator=(const Botan::MemoryRegion<T>&)': ../../src/Botan-1.8.8/build/include/botan/secmem.h:310: error: missing template arguments before '(' token What is this compiler error telling me? Here is a snippet of secmem.h that includes line 130: [...] /** * This class represents variable length buffers that do not * make use of memory locking. */ template<typename T> class MemoryVector : public MemoryRegion<T> { public: /** * Copy the contents of another buffer into this buffer. * @param in the buffer to copy the contents from * @return a reference to *this */ MemoryVector<T>& operator=(const MemoryRegion<T>& in) { if(this != &in) set(in); return (*this); } // This is line 130! [...]

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  • returning opengl display callback in D

    - by Max
    I've written a simple hello world opengl program in D, using the converted gl headers here. My code so far: import std.string; import c.gl.glut; Display_callback display() { return Display_callback // line 7 { return; // just display a blank window }; } // line 10 void main(string[] args) { glutInit(args.length, args); glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE); glutInitWindowSize(800,600); glutCreateWindow("Hello World"); glutDisplayFunc(display); glutMainLoop(); } My problem is with the display() function. glutDisplayFunc() expects a function that returns a Display_callback, which is typedef'd as typedef GLvoid function() Display_callback;. When I try to compile, dmd says line 7: found '{' when expecting ';' following return statement line 10: unrecognized declaration How do I properly return the Display_callback here? Also, how do I change D strings and string literals into char*? My calls to glutInit and glutCreateWindow don't like the D strings they're getting. Thanks for your help.

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  • Providing less than operator for one element of a pair

    - by Koszalek Opalek
    What would be the most elegant way too fix the following code: #include <vector> #include <map> #include <set> using namespace std; typedef map< int, int > row_t; typedef vector< row_t > board_t; typedef row_t::iterator area_t; bool operator< ( area_t const& a, area_t const& b ) { return( a->first < b->first ); }; int main( int argc, char* argv[] ) { int row_num; area_t it; set< pair< int, area_t > > queue; queue.insert( make_pair( row_num, it ) ); // does not compile }; One way to fix it is moving the definition of less< to namespace std (I know, you are not supposed to do it.) namespace std { bool operator< ( area_t const& a, area_t const& b ) { return( a->first < b->first ); }; }; Another obvious solution is defining less than< for pair< int, area_t but I'd like to avoid that and be able to define the operator only for the one element of the pair where it is not defined.

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  • Class Generics break completely seperate method

    - by TheLQ
    I found a strange problem when I used class Generics Today: Setting some broke a completely separate method. Here's a small example class that illustrates the problem. This code works just fine public class Sandbox { public interface ListenerManagerTest { public Set<Listener> getListeners(); } public void setListenerManager(ListenerManagerTest listenerManager) { for (Listener curListener : listenerManager.getListeners()) return; } } Now as soon as I use class Generics, the getListeners() method returns Set<Object> instead of Set<Listener> public class Sandbox { public interface ListenerManagerTest<E extends Object> { public Set<Listener> getListeners(); } public void setListenerManager(ListenerManagerTest listenerManager) { for (Listener curListener : listenerManager.getListeners()) //Expected Listener, not Object return; } } What would cause this error? The ##java channel on Freenode said it was because of compile time candy and that I was using a raw type. But how would an raw class type break all generics in the class? And how would of worked before?

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  • REST from asp.net 2.0

    - by weslleywang
    Hi, I just built a asp.net 2.0 web site. Now I need add REST web service so I can communicate with another web application. I've worked with 2 SOAP web service project before, but have no experise with REST at all. I guess only a coupleweeks would works fine. after googling, I found it's not that easy. This is what I found: There is NO REST out of box of asp.net. WCF REST Starter Kit Codeplex Preview 2 base on .net 3.5 and still in beta Rest ASP.NET Example REST Web Services in ASP.NET 2.0 (C#) Exyus Handling POST and PUT methods with Lullaby ADO.NET Data Service ... Now my question, a) Is a REST solution for .net 2.0? if yes, which one is best solution? b) if I have to, how hard to migrate my asp.net from 2.0 to 3.5? is it as simple as just compile, or I have to change a lot code? c) WCF REST Starter Kit is good enough to use in production? d) Do I have to learn WCF first, then WCF REST Starter Kit? where is the best place to start? I appreciate any help here. Thanks Wes

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  • Process xml-like log file queue

    - by Zsolt Botykai
    Hi all, first of all: I'm not a programmer, never was, although had learn a lot during my professional carreer as a support consultant. Now my task is to process - and create some statistics about a constantly written and rapidly growing XML like log file. It's not valid XML, because it does not have a proper <root> element, e.g. the log looks like this: <log itemdate="somedate"> <field id="0" /> ... </log> <log itemdate="somedate+1"> <field id="0" /> ... </log> <log itemdate="somedate+n"> <field id="0" /> ... </log> E.g. I have to count all the items with field id=0. But most of the solutions I had found (e.g. using XPath) reports an error about the garbage after the first closing </log>. Most probably I can use python (2.6, although I can compile 3.x as well), or some really old perl version (5.6.x), and recently compiled xmlstarlet which really looks promising - I was able to create the statistics for a certain period after copying the file, and pre- & appending the opening and closing root element. But this is a huge file and copying takes time as well. Isn't there a better solution? Thanks in advance!

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  • Increasing time resolution of BOOST::progress timer

    - by feelfree
    BOOST::progress_timer is a very useful class to measure the running time of a function. However, the default implementation of progress_timer is not accurate enough and a possible way of increasing time resolution is to reconstruct a new class as the following codes show: #include <boost/progress.hpp> #include <boost/static_assert.hpp> template<int N=2> class new_progress_timer:public boost::timer { public: new_progress_timer(std::ostream &os=std::cout):m_os(os) { BOOST_STATIC_ASSERT(N>=0 &&N<=10); } ~new_progress_timer(void) { try { std::istream::fmtflags old_flags = m_os.setf(std::istream::fixed,std::istream::floatfield); std::streamsize old_prec = m_os.precision(N); m_os<<elapsed()<<"s\n" <<std::endl; m_os.flags(old_flags); m_os.precison(old_prec); } catch(...) { } } private: std::ostream &m_os; }; However, when I compile the codes with VC10, the following error appear: 'precison' : is not a member of 'std::basic_ostream<_Elem,_Traits>' Any ideas? Thanks.

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  • Constraint to array dimension in C language

    - by Summer_More_More_Tea
    int KMP( const char *original, int o_len, const char *substring, int s_len ){ if( o_len < s_len ) return -1; int k = 0; int cur = 1; int fail[ s_len ]; fail[ k ] = -1; while( cur < s_len ){ k = cur - 1; do{ if( substring[ cur ] == substring[ k ] ){ fail[ cur ] = k; break; }else{ k = fail[ k ] + 1; } }while( k ); if( !k && ( substring[ cur ] != substring[ 0 ] ) ){ fail[ cur ] = -1; }else if( !k ){ fail[ cur ] = 0; } cur++; } k = 0; cur = 0; while( ( k < s_len ) && ( cur < o_len ) ){ if( original[ cur ] == substring[ k ] ){ cur++; k++; }else{ if( k == 0 ){ cur++; }else{ k = fail[ k - 1 ] + 1; } } } if( k == s_len ) return cur - k; else return -1; } This is a KMP algorithm I once coded. When I reviewed it this morning, I find it strange that an integer array is defined as int fail[ s_len ]. Does the specification requires dimesion of arrays compile-time constant? How can this code pass the compilation? By the way, my gcc version is 4.4.1. Thanks in advance!

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  • Which compiler option I should choose?

    - by Surjya Narayana Padhi
    Hi Geeks, I have to use the third party static library for my qt application to run on windows. The third party provides me a .lib and .h file for use. These libraries are compiled with MSVC compiler. My qt Creator is using MinGW compiler to compile my application. I copied the .h and .lib file to my qt project directory and then added those in .pro file as follows QT += core gui TARGET = MyTest TEMPLATE = app LIBS += C:\Qt\2010.05\qt\MyTest\newApi.lib SOURCES += main.cpp\ mainwindow.cpp HEADERS += mainwindow.h \ newApi.h FORMS += mainwindow.ui Now I am getting some runtime error like this - Starting C:\Qt\2010.05\qt\MyTest-build-desktop\debug\MyTest.exe... C:\Qt\2010.05\qt\MyTest-build-desktop\debug\MyTest.exe exited with code -1073741515 Can any body suggest is this runtime error is due to mismatch of compiler? (because of my .lib file I added is comipled in MSVC compiler and my qt app is compiled using MinGW compiler) If not what may be the reason? Am I missing anything in adding the .h and .lib file to my qt project? If my MinGW compiler will not support the .lib file generated in MSVC compiler what may be the work-arround? Can I create the .lib files in MinGW compiler? or this format is supported only by MSVC compiler only? Please suggest...

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  • char[] and char* compatibility?

    - by Aerovistae
    In essence, will this code work? And before you say "Run it and see!", I just realized my cygwin didn't come with gcc and it's currently 40 minutes away from completing reinstallation. That being said: char* words[1000]; for(int i = 0; i<1000; i++) words[i] = NULL; char buffer[ 1024 ]; //omit code that places "ADD splash\0" into the buffer if(strncmp (buffer, "ADD ", 4){ char* temp = buffer + 4; printf("Adding: %s", temp); int i = 0; while(words[i] != NULL) i++; words[i] = temp; } I'm mostly uncertain about the line char* temp = buffer + 4, and also whether I can assign words[i] in the manner that I am. Am I going to get type errors when I eventually try to compile this in 40 minutes? Also-- if this works, why don't I need to use malloc() on each element of words[]? Why can I say words[i] = temp, instead of needing to allocate memory for words[i] the length of temp?

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  • How to extract the Sql Command from a Complied Linq Query

    - by Harry
    In normal (not compiled) Linq to Sql queries you can extract the SQLCommand from the IQueryable via the following code: SqlCommand cmd = (SqlCommand)table.Context.GetCommand(query); Is it possible to do the same for a compiled query? The following code provides me with a delegate to a compiled query: private static readonly Func<Data.DAL.Context, string, IQueryable<Word>> Query_Get = CompiledQuery.Compile<Data.DAL.Context, string, IQueryable<Word>>( (context, name) => from r in context.GetTable<Word>() where r.Name == name select r); When i use this to generate the IQueryable and attempt to extract the SqlCommand it doesn't seem to work. When debugging the code I can see that the SqlCommand returned has the 'very' useful CommandText of 'SELECT NULL AS [EMPTY]' using (var db = new Data.DAL.Context()) { IQueryable<Word> query = Query_Get(db, "word"); SqlCommand cmd = (SqlCommand)db.GetCommand(query); Console.WriteLine(cmd != null ? cmd.CommandText : "Command Not Found"); } I can't find anything in google about this particular scenario, as no doubt it is not a common thing to attempt... So.... Any thoughts?

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  • Sonata Media Bundle sortBy created_at

    - by tony908
    I use SonataMediaBundle and i would like sort Gallery by created_at field. In repository class i have (without orderBy working good!): $qb = $this->createQueryBuilder('m') ->orderBy('j.expires_at', 'DESC'); $query = $qb->getQuery(); return $query->getResult(); and this throw error: An exception has been thrown during the rendering of a template ("[Semantical Error] line 0, col 80 near 'created_at D': Error: Class Application\Sonata\MediaBundle\Entity\Gallery has no field or association named created_at") so i add this field to Gallery class: /** * @var \DateTime */ private $created_at; /** * Set created_at * * @param \DateTime $createdAt * @return Slider */ public function setCreatedAt($createdAt) { $this->created_at = $createdAt; return $this; } /** * Get created_at * * @return \DateTime */ public function getCreatedAt() { return $this->created_at; } but now i have error: FatalErrorException: Compile Error: Declaration of Application\Sonata\MediaBundle\Entity\Gallery::setCreatedAt() must be compatible with Sonata\MediaBundle\Model\GalleryInterface::setCreatedAt(DateTime $createdAt = NULL) in /home/tony/www/test/Application/Sonata/MediaBundle/Entity/Gallery.php line 32 GalleryInterface: https://github.com/sonata-project/SonataMediaBundle/blob/master/Model/GalleryInterface.php So... how can i use sortBy in my example?

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  • Segmentation fault in C recursive Combination (nCr)

    - by AruniRC
    PLease help me out here. The program is supposed to recursively find out the combination of two numbers. nCr = n!/ (r!(n-r)! ). I'm getting this error message when i compile it on GCC. Here's what the terminal shows: Enter two numbers: 8 4 Segmentation fault (Program exited with code:139) The code is given here: #include<stdio.h> float nCr(float, float, float); int main() { float a, b, c; printf("Enter two numbers: \n"); scanf("%f%f", &a, &b); c = nCr(a, b, a-b); printf("\n%.3f", c); return 0; } float nCr(float n, float r, float p) { if(n<1) return (1/(p*r))*(nCr(1, r-1, p-1)); if(r<1) return (n/(p*1))*(nCr(n-1, 1, p-1)); if(p<1) return (n/r)*(nCr(n-1, r-1, 1)); return ( n/(p*r) )*nCr(n-1, r-1, p-1); }

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  • Adventures on Enterprise Library 5.0: Who moved my cheese (namespace)

    - by Junior Mayhé
    Jesus, Krishna, Budda! I've migrated to EntLib 5.0, but classes like ISymmetricCryptoProvider are not recognized anymore. Funny to say that Data, Logging and other blocks are working compiling fine. Here's the problematic class: using System; using System.Collections.Generic; using System.Text; using Microsoft.Practices.EnterpriseLibrary.Common.Configuration;//-->it's not working anymore using Microsoft.Practices.EnterpriseLibrary.Security.Cryptography;//-->it's not working anymore namespace MyClassLibrary.Security.EnterpriseLibrary { public sealed class Crypto { public static ISymmetricCryptoProvider MyProvider { get { //IConfigurationSource is not recognized either, neither SystemConfigurationSource IConfigurationSource cs = new SystemConfigurationSource(); SymmetricCryptoProviderFactory scpf = new SymmetricCryptoProviderFactory(cs); ISymmetricCryptoProvider p = scpf.CreateDefault(); return p; } } The references are fine on project too. I really don't know why this particular project it's causing too many trouble on VS2010! Older references were deleted, project was cleaned, rebuilt, but can't make it compile :-( The references are: Microsoft.Practices.EnterpriseLibrary.Common Microsoft.Practices.EnterpriseLibrary.Logging Microsoft.Practices.EnterpriseLibrary.Logging.Database Microsoft.Practices.EnterpriseLibrary.Security Microsoft.Practices.EnterpriseLibrary.Security.Cryptography Why some namespaces can be found while others can't?

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  • The Current State Of Serving a PHP 5.x App on the Apache, LightTPD & Nginx Web Servers?

    - by Gregory Kornblum
    Being stuck in a MS stack architecture/development position for the last year and a half has prevented me from staying on top of the world of open source stack based web servers recent evolution more than I would have liked to. However I am now building an open source stack based application/system architecture and sadly I do not have the time to give each of the above mentioned web servers a thorough test of my own to decide. So I figured I'd get input from the best development community site and more specifically the people who make it so. This is a site that is a resource for information regarding a specific domain and target audience with features to help users not only find the information but to also interact with one another in various ways for various reasons. I chose the open source stack for the wealth of resources it has along with much better offers than the MS stack (i.e. WordPress vs BlogEngine.NET). I feel Java is more in the middle of these stacks in this regard although I am not ruling out the possibility of using it in certain areas unrelated to the actual web app itself such as background processes. I have already come to the conclusion of using PHP (using CodeIgniter framework & APC), MySQL (InnoDB) and Memcached on CentOS. I am definitely serving static content on Nginx. However the 3 servers mentioned have no consensus on which is best for dynamic content in regards to performance. It seems LightTPD still has the leak issue which rules it out if it does, Nginx seems it is still not mature enough for this aspect and of course Apache tries to be everything for everybody. I am still going to compile the one chosen with as many performance tweaks as possible such as static linking and the likes. I believe I can get Apache to match the other 2 in regards to serving dynamic content through this process and not having it serve anything static. However during my research it seems the others are still worth considering. So with all things considered I would love to hear what everyone here has to say on the matter. Thanks!

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  • Python Loop for mysql statement

    - by user552974
    Hi, I have a project that i need to compile number of cities in each state and make an insert statement for mysql database. I think the easiest way to do it is via python but since i m a complete noob i would like to reach out all the python gurus here. Here is what the input looks like. Example below is for Florida. cities = ['Boca Raton', 'Boynton Beach', 'Bradenton', 'Cape Coral', 'Deltona'] and this what the output should be. INSERT INTO `oc_locations` (`idLocation`, `name`, `idLocationParent`, `friendlyName`) VALUES (1, 'Florida', 0, 'Florida'), (2, 'Boca Raton', 1, 'Boca Raton'), (3, 'Boynton Beach', 1, 'Boynton Beach'), (4, 'Bradenton', 1, 'Bradenton'), (5, 'Cape Coral', 1, 'Cape Coral'), (6, 'Deltona', 1, 'Deltona'), If you look at carefully the "idLocationParent" for "Florida" value is "0" so which means it is a top level value. This will be done for 50 states so ability to plug the state name into the mysql statement would be icing on the cake if there is a easy way to do it. Also alphabetical order and auto increment for the idLocation would be great. Here is an example of what i m trying to achieve concatenation is the part i need to figure out. for city in cities: print (1, 'city', 0, 'city'), city

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  • C++ using typedefs in non-inline functions

    - by ArunSaha
    I have a class like this template< typename T > class vector { public: typedef T & reference; typedef T const & const_reference; typedef size_t size_type; const_reference at( size_t ) const; reference at( size_t ); and later in the same file template< typename T > typename vector<T>::const_reference // Line X vector<T>::at( size_type i ) const { rangecheck(); return elems_[ i ]; } template< typename T > reference // Line Y vector<T>::at( size_type i ) { rangecheck(); return elems_[ i ]; } Line X compiles fine but Line Y does not compile. The error message from g++ (version 4.4.1) is: foo.h:Y: error: expected initializer before 'vector' From this I gather that, if I want to have non-inline functions then I have to fully qualify the typedef name as in Line X. (Note that, there is no problem for size_type.) However, at least to me, Line X looks clumsy. Is there any alternative approach?

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  • How to get address of va_arg?

    - by lionbest
    I hack some old C API and i got a compile error with the following code: void OP_Exec( OP* op , ... ) { int i; va_list vl; va_start(vl,op); for( i = 0; i < op->param_count; ++i ) { switch( op->param_type[i] ) { case OP_PCHAR: op->param_buffer[i] = va_arg(vl,char*); // ok it works break; case OP_INT: op->param_buffer[i] = &va_arg(vl,int); // error here break; // ... more here } } op->pexec(op); va_end(vl); } The error with gcc version 4.4.1 (Ubuntu 4.4.1-4ubuntu9) was: main.c|55|error: lvalue required as unary ‘&’ operand So why exactly it's not possible here to get a pointer to argument? How to fix it? This code is executed very often with different OP*, so i prefer to not allocate extra memory. Is it possible to iterate over va_list knowing only the size of arguments?

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  • How to Implement an Interface that Requires Duplicate Member Names?

    - by Will Marcouiller
    I often have to implement some interfaces such as IEnumerable<T> in my code. Each time, when implementing automatically, I encounter the following: public IEnumerator<T> GetEnumerator() { // Code here... } public IEnumerator GetEnumerator1() { // Code here... } Though I have to implement both GetEnumerator() methods, they impossibly can have the same name, even if we understand that they do the same, somehow. The compiler can't treat them as one being the overload of the other, because only the return type differs. When doing so, I manage to set the GetEnumerator1() accessor to private. This way, the compiler doesn't complaint about not implementing the interface member, and I simply throw a NotImplementedException within the method's body. However, I wonder whether it is a good practice, or if I shall proceed differently, as perhaps a method alias or something like so. What is the best approach while implementing an interface such as IEnumerable<T> that requires the implementation of two different methods with the same name? EDIT #1 Does VB.NET reacts differently from C# while implementing interfaces, since in VB.NET it is explicitly implemented, thus forcing the GetEnumerator1(). Here's the code: Public Function GetEnumerator() As System.Collections.Generic.IEnumerator(Of T) Implements System.Collections.Generic.IEnumerable(Of T).GetEnumerator // Code here... End Function Public Function GetEnumerator1() As System.Collections.Generic.IEnumerator Implements System.Collections.Generic.IEnumerable.GetEnumerator // Code here... End Function Both GetEnumerator() methods are explicitly implemented, and the compile will refuse them to have the same name. Why?

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  • Why won't WPF databindings show text when ToString() has a collaborating object?

    - by Jay
    In a simple form, I bind to a number of different objects -- some go in listboxes; some in textblocks. A couple of these objects have collaborating objects upon which the ToString() method calls when doing its work -- typically a formatter of some kind. When I step through the code I see that when the databinding is being set up, ToString() is called the collaborating object is not null and returns the expected result when inspected in the debugger, the objects return the expected result from ToString() BUT the text does not show up in the form. The only common thread I see is that these use a collaborating object, whereas the other bindings that show up as expected simply work from properties and methods of the containing object. If this is confusing, here is the gist in code: public class ThisThingWorks { private SomeObject some_object; public ThisThingWorks(SomeObject s) { some_object = s; } public override string ToString() { return some_object.name; } } public class ThisDoesntWork { private Formatter formatter; private SomeObject some_object; public ThisDoesntWork(SomeObject o, Formatter f) { formatter = f; some_object = o; } public override string ToString() { return formatter.Format(some_object.name); } } Again, let me reiterate -- the ToString() method works in every other context -- but when I bind to the object in WPF and expect it to display the result of ToString(), I get nothing. Update: The issue seems to be what I see as a buggy behaviour in the TextBlock binding. If I bind the Text property to a property of the DataContext that is declared as an interface type, ToString() is never called. If I change the property declaration to an implementation of the interface, it works as expected. Other controls, like Label work fine when binding the Content property to a DataContext property declared as either the implementation or the interface. Because this is so far removed from the title and content of this question, I've created a new question here: http://stackoverflow.com/questions/2917878/why-doesnt-textblock-databinding-call-tostring-on-a-property-whose-compile-tim

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  • QObject::connect not connecting signal to slot

    - by user1662800
    I am using C++ and Qt in my project and my problem is QObject::connect function doesn't connect signal to a slot. I have the following classes: class AddCommentDialog : public QDialog { Q_OBJECT public: ...some functions signals: void snippetAdded(); private slots: void on_buttonEkle_clicked(); private: Ui::AddCommentDialog *ui; QString snippet; }; A part of my Main window: class MainWindow : public QMainWindow { Q_OBJECT public: explicit MainWindow(QWidget *parent = 0); ~MainWindow(); private slots: void commentAddedSlot(); void variableAddedSlot(); ... private: AddCommentDialog *addCommentDialog; ... }; Ant the last dialog; class AddDegiskenDialog : public QDialog { Q_OBJECT public: ... signals: void variableAdded(); private slots: void on_buttonEkle_clicked(); private: Ui::AddDegiskenDialog *ui; ... }; In the main window constructor i connect signals and slots: addCommentDialog=new AddCommentDialog(); addDegiskenDialog=new AddDegiskenDialog(); connect(addDegiskenDialog, SIGNAL(variableAdded()), this, SLOT(variableAddedSlot())); connect(addCommentDialog, SIGNAL(snippetAdded()), this, SLOT(commentAddedSlot())); The point is my commentAddedSlot is connected to it's signal successfully, but commentAddedSlot is failed. There is the Q_OBJECT macros, no warning such as about no x slot. In addition to this, receivers(SIGNAL(snippetAdded())) gives me 1 but receivers(SIGNAL(variableAdded())) gives me 0 and i used commands qmake -project; qmake and make to fully compile. What am i missing?

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  • Recursive templates: compilation error under g++

    - by Johannes
    Hi, I am trying to use templates recursively to define (at compile-time) a d-tuple of doubles. The code below compiles fine with Visual Studio 2010, but g++ fails and complains that it "cannot call constructor 'point<1::point' directly". Could anyone please shed some light on what is going on here? Many thanks, Jo #include <iostream> #include <utility> using namespace std; template <const int N> class point { private: pair<double, point<N-1> > coordPointPair; public: point() { coordPointPair.first = 0; coordPointPair.second.point<N-1>::point(); } }; template<> class point<1> { private: double coord; public: point() { coord= 0; } }; int main() { point<5> myPoint; return 0; }

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