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  • How I can compile this C++ code that fails with "'::main' must return 'int'"? [migrated]

    - by krisu
    I have tried to find a solution that make batch file start flashing on taskbar and only good solution was this post on Stack Overflow. But I can't compile the code with WinGW or anything else to EXE, only getting this error: hello.cpp:6:32: error: '::main' must return 'int' Right now, I'm using TDM-GCC to compile code, because it's bit better... Can somebody give me code that actually works or even better compile it to EXE already? P.S. Even more better if somebody could compile this Delphi code, because I can't find any software that's free.

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  • How to setup KVM partitioning?

    - by Richard
    I'm trying to install SolusVM/KVM on a server with one 500 GB HD and one 256 SSD. I am a complete beginner at Linux. SolusVM has a script on the site to download and install automatically, but how do I specify to install the script on the 500 GB HD and put the virtual machines on the SSD? And how should my partitioning look like? I want KVM isos and stuff on HD and virtual machines on SSD. Thanks a lot.

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  • boost::asio::async_read_until problem

    - by user368831
    I'm trying to modify the echo server example from boost asio and I'm running into problem when I try to use boost::asio::async_read_until. Here's the code: #include <cstdlib> #include <iostream> #include <boost/bind.hpp> #include <boost/asio.hpp> using boost::asio::ip::tcp; class session { public: session(boost::asio::io_service& io_service) : socket_(io_service) { } tcp::socket& socket() { return socket_; } void start() { std::cout<<"starting"<<std::endl; boost::asio::async_read_until(socket_, boost::asio::buffer(data_, max_length), ' ', boost::bind(&session::handle_read, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); } void handle_read(const boost::system::error_code& error, size_t bytes_transferred) { std::cout<<"handling read"<<std::endl; if (!error) { boost::asio::async_write(socket_, boost::asio::buffer(data_, bytes_transferred), boost::bind(&session::handle_write, this, boost::asio::placeholders::error)); } else { delete this; } } void handle_write(const boost::system::error_code& error) { if (!error) { /* socket_.async_read_some(boost::asio::buffer(data_, max_length), boost::bind(&session::handle_read, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); */ } else { delete this; } } private: tcp::socket socket_; enum { max_length = 1024 }; char data_[max_length]; }; class server { public: server(boost::asio::io_service& io_service, short port) : io_service_(io_service), acceptor_(io_service, tcp::endpoint(tcp::v4(), port)) { session* new_session = new session(io_service_); acceptor_.async_accept(new_session->socket(), boost::bind(&server::handle_accept, this, new_session, boost::asio::placeholders::error)); } void handle_accept(session* new_session, const boost::system::error_code& error) { if (!error) { new_session->start(); new_session = new session(io_service_); acceptor_.async_accept(new_session->socket(), boost::bind(&server::handle_accept, this, new_session, boost::asio::placeholders::error)); } else { delete new_session; } } private: boost::asio::io_service& io_service_; tcp::acceptor acceptor_; }; int main(int argc, char* argv[]) { try { if (argc != 2) { std::cerr << "Usage: async_tcp_echo_server <port>\n"; return 1; } boost::asio::io_service io_service; using namespace std; // For atoi. server s(io_service, atoi(argv[1])); io_service.run(); } catch (std::exception& e) { std::cerr << "Exception: " << e.what() << "\n"; } return 0; } The problem is when I try to compile I get this weird error: server.cpp: In member function ‘void session::start()’: server.cpp:27: error: no matching function for call to ‘async_read_until(boost::asio::basic_stream_socket &, boost::asio::mutable_buffers_1, char, boost::_bi::bind_t, boost::_bi::list3, boost::arg<1 ()(), boost::arg<2 ()() )’ Can someone please explain what's going on? From what I can tell the arguments to async_read_until are correct. Thanks!

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  • boost fusion: strange problem depending on number of elements on a vector

    - by ChAoS
    I am trying to use Boost::Fusion (Boost v1.42.0) in a personal project. I get an interesting error with this code: #include "boost/fusion/include/sequence.hpp" #include "boost/fusion/include/make_vector.hpp" #include "boost/fusion/include/insert.hpp" #include "boost/fusion/include/invoke_procedure.hpp" #include "boost/fusion/include/make_vector.hpp" #include <iostream> class Class1 { public: typedef boost::fusion::vector<int,float,float,char,int,int> SequenceType; SequenceType s; Class1(SequenceType v):s(v){} }; class Class2 { public: Class2(){} void met(int a,float b ,float c ,char d ,int e,int f) { std::cout << a << " " << b << " " << c << " " << d << " " << e << std::endl; } }; int main(int argn, char**) { Class2 p; Class1 t(boost::fusion::make_vector(9,7.66f,8.99f,'s',7,6)); boost::fusion::begin(t.s); //OK boost::fusion::insert(t.s, boost::fusion::begin(t.s), &p); //OK boost::fusion::invoke_procedure(&Class2::met,boost::fusion::insert(t.s, boost::fusion::begin(t.s), &p)); //FAILS } It fails to compile (gcc 4.4.1): In file included from /home/thechaos/Escriptori/of_preRelease_v0061_linux_FAT/addons/ofxTableGestures/ext/boost/fusion/include/invoke_procedur e.hpp:10, from problema concepte.cpp:11: /home/thechaos/Escriptori/of_preRelease_v0061_linux_FAT/addons/ofxTableGestures/ext/boost/fusion/functional/invocation/invoke_procedure.hpp: I n function ‘void boost::fusion::invoke_procedure(Function, const Sequence&) [with Function = void (Class2::*)(int, float, float, char, int, in t), Sequence = boost::fusion::joint_view<boost::fusion::joint_view<boost::fusion::iterator_range<boost::fusion::vector_iterator<const boost::f usion::vector<int, float, float, char, int, int, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_>, 0>, boost::fusion::vector_iterator<boost::fusion::vector<int, float, float, char, int, int, boost::fusion::void_, boost::fusion::void_, boost::fus ion::void_, boost::fusion::void_>, 0> >, const boost::fusion::single_view<Class2*> >, boost::fusion::iterator_range<boost::fusion::vector_iter ator<boost::fusion::vector<int, float, float, char, int, int, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion: :void_>, 0>, boost::fusion::vector_iterator<const boost::fusion::vector<int, float, float, char, int, int, boost::fusion::void_, boost::fusion ::void_, boost::fusion::void_, boost::fusion::void_>, 6> > >]’: problema concepte.cpp:39: instantiated from here /home/thechaos/Escriptori/of_preRelease_v0061_linux_FAT/addons/ofxTableGestures/ext/boost/fusion/functional/invocation/invoke_procedure.hpp:88 : error: incomplete type ‘boost::fusion::detail::invoke_procedure_impl<void (Class2::*)(int, float, float, char, int, int), const boost::fusio n::joint_view<boost::fusion::joint_view<boost::fusion::iterator_range<boost::fusion::vector_iterator<const boost::fusion::vector<int, float, f loat, char, int, int, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_>, 0>, boost::fusion::vector_itera tor<boost::fusion::vector<int, float, float, char, int, int, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion:: void_>, 0> >, const boost::fusion::single_view<Class2*> >, boost::fusion::iterator_range<boost::fusion::vector_iterator<boost::fusion::vector< int, float, float, char, int, int, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_>, 0>, boost::fusion: :vector_iterator<const boost::fusion::vector<int, float, float, char, int, int, boost::fusion::void_, boost::fusion::void_, boost::fusion::voi d_, boost::fusion::void_>, 6> > >, 7, true, false>’ used in nested name specifier However, if I change the number of arguments in the vectors and the method from 6 to 5 from int,float,float,char,int,int to int,float,float,char,int,I can compile it without problems. I suspected about the maximum number of arguments being a limitation, but I tried to change it through defining FUSION_MAX_VECTOR_SIZE without success. I am unable to see what am I doing wrong. Can you reproduce this? Can it be a boost bug (i doubt it but is not impossible)?

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  • C++ virtual functions.Problem with vtable

    - by adivasile
    I'm doing a little project in C++ and I've come into some problems regarding virtual functions. I have a base class with some virtual functions: #ifndef COLLISIONSHAPE_H_ #define COLLISIONSHAPE_H_ namespace domino { class CollisionShape : public DominoItem { public: // CONSTRUCTOR //------------------------------------------------- // SETTERS //------------------------------------------------- // GETTERS //------------------------------------------------- virtual void GetRadius() = 0; virtual void GetPosition() = 0; virtual void GetGrowth(CollisionShape* other) = 0; virtual void GetSceneNode(); // OTHER //------------------------------------------------- virtual bool overlaps(CollisionShape* shape) = 0; }; } #endif /* COLLISIONSHAPE_H_ */ and a SphereShape class which extends CollisionShape and implements the methods above /* SphereShape.h */ #ifndef SPHERESHAPE_H_ #define SPHERESHAPE_H_ #include "CollisionShape.h" namespace domino { class SphereShape : public CollisionShape { public: // CONSTRUCTOR //------------------------------------------------- SphereShape(); SphereShape(CollisionShape* shape1, CollisionShape* shape2); // DESTRUCTOR //------------------------------------------------- ~SphereShape(); // SETTERS //------------------------------------------------- void SetPosition(); void SetRadius(); // GETTERS //------------------------------------------------- cl_float GetRadius(); cl_float3 GetPosition(); SceneNode* GetSceneNode(); cl_float GetGrowth(CollisionShape* other); // OTHER //------------------------------------------------- bool overlaps(CollisionShape* shape); }; } #endif /* SPHERESHAPE_H_ */ and the .cpp file: /*SphereShape.cpp*/ #include "SphereShape.h" #define max(a,b) (a>b?a:b) namespace domino { // CONSTRUCTOR //------------------------------------------------- SphereShape::SphereShape(CollisionShape* shape1, CollisionShape* shape2) { } // DESTRUCTOR //------------------------------------------------- SphereShape::~SphereShape() { } // SETTERS //------------------------------------------------- void SphereShape::SetPosition() { } void SphereShape::SetRadius() { } // GETTERS //------------------------------------------------- void SphereShape::GetRadius() { } void SphereShape::GetPosition() { } void SphereShape::GetSceneNode() { } void SphereShape::GetGrowth(CollisionShape* other) { } // OTHER //------------------------------------------------- bool SphereShape::overlaps(CollisionShape* shape) { return true; } } These classes, along some other get compiled into a shared library. Building libdomino.so g++ -m32 -lpthread -ldl -L/usr/X11R6/lib -lglut -lGLU -lGL -shared -lSDKUtil -lglut -lGLEW -lOpenCL -L/home/adrian/AMD-APP-SDK-v2.4-lnx32/lib/x86 -L/home/adrian/AMD-APP-SDK-v2.4-lnx32/TempSDKUtil/lib/x86 -L"/home/adrian/AMD-APP-SDK-v2.4-lnx32/lib/x86" -lSDKUtil -lglut -lGLEW -lOpenCL -o build/debug/x86/libdomino.so build/debug/x86//Material.o build/debug/x86//Body.o build/debug/x86//SphereShape.o build/debug/x86//World.o build/debug/x86//Engine.o build/debug/x86//BVHNode.o When I compile the code that uses this library I get the following error: ../../../lib/x86//libdomino.so: undefined reference to `vtable for domino::CollisionShape' ../../../lib/x86//libdomino.so: undefined reference to `typeinfo for domino::CollisionShape' Command used to compile the demo that uses the library: g++ -o build/debug/x86/startdemo build/debug/x86//CMesh.o build/debug/x86//CSceneNode.o build/debug/x86//OFF.o build/debug/x86//Light.o build/debug/x86//main.o build/debug/x86//Camera.o -m32 -lpthread -ldl -L/usr/X11R6/lib -lglut -lGLU -lGL -lSDKUtil -lglut -lGLEW -ldomino -lSDKUtil -lOpenCL -L/home/adrian/AMD-APP-SDK-v2.4-lnx32/lib/x86 -L/home/adrian/AMD-APP-SDK-v2.4-lnx32/TempSDKUtil/lib/x86 -L../../../lib/x86/ -L"/home/adrian/AMD-APP-SDK-v2.4-lnx32/lib/x86" (the -ldomino flag) And when I run the demo, I manually tell it about the library: LD_LIBRARY_PATH=../../lib/x86/:$AMDAPPSDKROOT/lib/x86:$LD_LIBRARY_PATH bin/x86/startdemo After reading a bit about virtual functions and virtual tables I understood that virtual tables are handled by the compiler and I shouldn't worry about it, so I'm a little bit confused on how to handle this issue. I'm using gcc version 4.6.0 20110530 (Red Hat 4.6.0-9) (GCC) Later edit: I'm really sorry, but I wrote the code by hand directly here. I have defined the return types in the code. I apologize to the 2 people that answered below. I have to mention that I am a beginner at using more complex project layouts in C++.By this I mean more complex makefiles, shared libraries, stuff like that.

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  • Cross Compiling Boost for use on the Gumstix Overo with GumROS

    - by amelim
    I'm trying to cross-compile boost for use with the ROS framework on a Gumstix Overo. I've been following the posted instructions here (modifying the script when need be), however I've come across an issue where bjam will not compile boost properly. I call bjam as follows: # boost if [ ! -f /opt/gumros/lib/libboost_date_time-gcc41-mt-1_38.so ] ; then if [ ! -f boost_1_38_0.tar.gz ] ; then wget --tries=10 http://heanet.dl.sourceforge.net/sourceforge/boost/boost_1_38_0.tar.gz fi # tar xzf boost_1_38_0.tar.gz cd boost_1_38_0 GPP_PATH=${OVEROTOP}/tmp/cross/armv7a/arm-angstrom-linux-gnueabi/bin/g++ GPP_VER=`${GPP_PATH} -v 2>&1 | tail -1 | awk '{print $3}'` echo "using gcc : ${GPP_VER} : ${GPP_PATH} ; " > tools/build/v2/user-config.jam sudo apt-get install bjam set +o errexit sudo bjam --toolset=gcc-${GPP_VER} --prefix=/opt/gumros --with-date_time install set -o errexit cd .. else echo "boost appears to be already installed; skipping." fi if [ ! -f /opt/gumros/lib/libboost_date_time-gcc41-mt-1_38.so ] ; then echo "Failed to compile libboost_date_time"; exit; fi I've checked the user-config to make sure everything was kosher as well as making sure the GPP_PATH is correct. However, when I run the scrip I come across compilation errors such as: Reading package lists... Done Building dependency tree Reading state information... Done bjam is already the newest version. 0 upgraded, 0 newly installed, 0 to remove and 5 not upgraded. ...patience... ...found 14370 targets... ...updating 14 targets... gcc.compile.c++ bin.v2/libs/date_time/build/gcc-4.3.3/release/threading-multi/gregorian/greg_month.o g++: error trying to exec 'cc1plus': execvp: No such file or directory "/home/andrew/overo-oe/tmp/cross/armv7a/arm-angstrom-linux-gnueabi/bin/g++" -ftemplate-depth-128 -O3 -finline-functions -Wno-inline -Wall -pthread -fPIC -DBOOST_ALL_DYN_LINK=1 -DBOOST_ALL_NO_LIB=1 -DDATE_TIME_INLINE -DNDEBUG -I"." -c -o "bin.v2/libs/date_time/build/gcc-4.3.3/release/threading-multi/gregorian/greg_month.o" "libs/date_time/src/gregorian/greg_month.cpp" ...failed gcc.compile.c++ bin.v2/libs/date_time/build/gcc-4.3.3/release/threading-multi/gregorian/greg_month.o... gcc.compile.c++ bin.v2/libs/date_time/build/gcc-4.3.3/release/threading-multi/gregorian/greg_weekday.o g++: error trying to exec 'cc1plus': execvp: No such file or directory "/home/andrew/overo-oe/tmp/cross/armv7a/arm-angstrom-linux-gnueabi/bin/g++" -ftemplate-depth-128 -O3 -finline-functions -Wno-inline -Wall -pthread -fPIC -DBOOST_ALL_DYN_LINK=1 -DBOOST_ALL_NO_LIB=1 -DDATE_TIME_INLINE -DNDEBUG -I"." -c -o "bin.v2/libs/date_time/build/gcc-4.3.3/release/threading-multi/gregorian/greg_weekday.o" "libs/date_time/src/gregorian/greg_weekday.cpp" ...failed gcc.compile.c++ bin.v2/libs/date_time/build/gcc-4.3.3/release/threading-multi/gregorian/greg_weekday.o... gcc.compile.c++ bin.v2/libs/date_time/build/gcc-4.3.3/release/threading-multi/gregorian/date_generators.o g++: error trying to exec 'cc1plus': execvp: No such file or directory Etc... For reference, I'm using this tutorial to help me out. http://www.ros.org/wiki/gumros

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  • Can't access a map member from a pointer

    - by fjfnaranjo
    Hi. That's my first question :) I'm storing the configuration of my program in a Group->Key->Value form, like the old INIs. I'm storing the information in a pair of structures. First one, I'm using a std::map with string+ptr for the groups info (the group name in the string key). The second std::map value is a pointer to the sencond structure, a std::list of std::maps, with the finish Key->Value pairs. The Key-Value pairs structure is created dynamically, so the config structure is: std::map< std::string , std::list< std::map<std::string,std::string> >* > lv1; Well, I'm trying to implement two methods to check the existence of data in the internal config. The first one, check the existence of a group in the structure: bool isConfigLv1(std::string); bool ConfigManager::isConfigLv1(std::string s) { return !(lv1.find(s)==lv1.end()); } The second method, is making me crazy... It check the existence for a key inside a group. bool isConfigLv2(std::string,std::string); bool ConfigManager::isConfigLv2(std::string s,std::string d) { if(!isConfigLv1(s)) return false; std::map< std::string , std::list< std::map<std::string,std::string> >* >::iterator it; std::list< std::map<std::string,std::string> >* keyValue; std::list< std::map<std::string,std::string> >::iterator keyValueIt; it = lv1.find(s); keyValue = (*it).second; for ( keyValueIt = keyValue->begin() ; keyValueIt != keyValue->end() ; keyValueIt++ ) if(!((*keyValueIt).second.find(d)==(*keyValueIt).second.end())) return true; return false; } I don't understand what is wrong. The compiler says: ConfigManager.cpp||In member function ‘bool ConfigManager::isConfigLv2(std::string, std::string)’:| ConfigManager.cpp|(line over return true)|error: ‘class std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >’ has no member named ‘second’| But it has to have the second member, because it's a map iterator... Any suggestion about what's happening? Sorry for my English :P, and consider I'm doing it as a exercise, I know there are a lot of cool configuration managers.

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  • Scope quandary with namespaces, function templates, and static data

    - by Adrian McCarthy
    This scoping problem seems like the type of C++ quandary that Scott Meyers would have addressed in one of his Effective C++ books. I have a function, Analyze, that does some analysis on a range of data. The function is called from a few places with different types of iterators, so I have made it a template (and thus implemented it in a header file). The function depends on a static table of data, AnalysisTable, that I don't want to expose to the rest of the code. My first approach was to make the table a static const inside Analysis. namespace MyNamespace { template <typename InputIterator> int Analyze(InputIterator begin, InputIterator end) { static const int AnalysisTable[] = { /* data */ }; ... // implementation uses AnalysisTable return result; } } // namespace MyNamespace It appears that the compiler creates a copy of AnalysisTable for each instantiation of Analyze, which is wasteful of space (and, to a small degree, time). So I moved the table outside the function like this: namespace MyNamespace { const int AnalysisTable[] = { /* data */ }; template <typename InputIterator> int Analyze(InputIterator begin, InputIterator end) { ... // implementation uses AnalysisTable return result; } } // namespace MyNamespace There's only one copy of the table now, but it's exposed to the rest of the code. I'd rather keep this implementation detail hidden, so I introduced an unnamed namespace: namespace MyNamespace { namespace { // unnamed to hide AnalysisTable const int AnalysisTable[] = { /* data */ }; } // unnamed namespace template <typename InputIterator> int Analyze(InputIterator begin, InputIterator end) { ... // implementation uses AnalysisTable return result; } } // namespace MyNamespace But now I again have multiple copies of the table, because each compilation unit that includes this header file gets its own. If Analyze weren't a template, I could move all the implementation detail out of the header file. But it is a template, so I seem stuck. My next attempt was to put the table in the implementation file and to make an extern declaration within Analyze. // foo.h ------ namespace MyNamespace { template <typename InputIterator> int Analyze(InputIterator begin, InputIterator end) { extern const int AnalysisTable[]; ... // implementation uses AnalysisTable return result; } } // namespace MyNamespace // foo.cpp ------ #include "foo.h" namespace MyNamespace { const int AnalysisTable[] = { /* data */ }; } This looks like it should work, and--indeed--the compiler is satisfied. The linker, however, complains, "unresolved external symbol AnalysisTable." Drat! (Can someone explain what I'm missing here?) The only thing I could think of was to give the inner namespace a name, declare the table in the header, and provide the actual data in an implementation file: // foo.h ----- namespace MyNamespace { namespace PrivateStuff { extern const int AnalysisTable[]; } // unnamed namespace template <typename InputIterator> int Analyze(InputIterator begin, InputIterator end) { ... // implementation uses PrivateStuff::AnalysisTable return result; } } // namespace MyNamespace // foo.cpp ----- #include "foo.h" namespace MyNamespace { namespace PrivateStuff { const int AnalysisTable[] = { /* data */ }; } } Once again, I have exactly one instance of AnalysisTable (yay!), but other parts of the program can access it (boo!). The inner namespace makes it a little clearer that they shouldn't, but it's still possible. Is it possible to have one instance of the table and to move the table beyond the reach of everything but Analyze?

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  • Qt 4.6 Adding objects and sub-objects to QWebView window object (C++ & Javascript)

    - by Cor
    I am working with Qt's QWebView, and have been finding lots of great uses for adding to the webkit window object. One thing I would like to do is nested objects... for instance: in Javascript I can... var api = new Object; api.os = new Object; api.os.foo = function(){} api.window = new Object(); api.window.bar = function(){} obviously in most cases this would be done through a more OO js-framework. This results in a tidy structure of: >>>api ------------------------------------------------------- - api Object {os=Object, more... } - os Object {} foo function() - win Object {} bar function() ------------------------------------------------------- Right now I'm able to extend the window object with all of the qtC++ methods and signals I need, but they all have 'seem' to have to be in a root child of "window". This is forcing me to write a js wrapper object to get the hierarchy that I want in the DOM. >>>api ------------------------------------------------------- - api Object {os=function, more... } - os_foo function() - win_bar function() ------------------------------------------------------- This is a pretty simplified example... I want objects for parameters, etc... Does anyone know of a way to pass an child object with the object that extends the WebFrame's window object? Here's some example code of how I'm adding the object: mainwindow.h #ifndef MAINWINDOW_H #define MAINWINDOW_H #include <QtGui/QMainWindow> #include <QWebFrame> #include "mainwindow.h" #include "happyapi.h" class QWebView; class QWebFrame; QT_BEGIN_NAMESPACE class MainWindow : public QMainWindow { Q_OBJECT public: MainWindow(QWidget *parent = 0); private slots: void attachWindowObject(); void bluesBros(); private: QWebView *view; HappyApi *api; QWebFrame *frame; }; #endif // MAINWINDOW_H mainwindow.cpp #include <QDebug> #include <QtGui> #include <QWebView> #include <QWebPage> #include "mainwindow.h" #include "happyapi.h" MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent) { view = new QWebView(this); view->load(QUrl("file:///Q:/example.htm")); api = new HappyApi(this); QWebPage *page = view->page(); frame = page->mainFrame(); attachWindowObject(); connect(frame, SIGNAL(javaScriptWindowObjectCleared()), this, SLOT(attachWindowObject())); connect(api, SIGNAL(win_bar()), this, SLOT(bluesBros())); setCentralWidget(view); }; void MainWindow::attachWindowObject() { frame->addToJavaScriptWindowObject(QString("api"), api); }; void MainWindow::bluesBros() { qDebug() << "foo and bar are getting the band back together!"; }; happyapi.h #ifndef HAPPYAPI_H #define HAPPYAPI_H #include <QObject> class HappyApi : public QObject { Q_OBJECT public: HappyApi(QObject *parent); public slots: void os_foo(); signals: void win_bar(); }; #endif // HAPPYAPI_H happyapi.cpp #include <QDebug> #include "happyapi.h" HappyApi::HappyApi(QObject *parent) : QObject(parent) { }; void HappyApi::os_foo() { qDebug() << "foo called, it want's it's bar back"; }; I'm reasonably new to C++ programming (coming from a web and python background). Hopefully this example will serve to not only help other new users, but be something interesting for a more experienced c++ programmer to elaborate on. Thanks for any assistance that can be provided. :)

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  • Concat wchar_t Unicode strings in C?

    - by Doori Bar
    I'm a beginner, I play with FindFirstFileW() of the winapi - C. The unicoded path is: " \\?\c:\Français\", and I would like to concat "*" to this path of type wchar_t (then I will use it as an arg for FindFirstFileW()). I made two test cases of mine, the first is ansi_string() which seem to work fine, the second is unicode_string() - which I don't quite understand how should I concat the additional "*" char to the unicoded path. I write the strings to a file, because I'm not able to print Unicoded characters to stdout. Note: my goal is to learn, which means I'll appreciate guidance and references to the appropriate resources regards my scenario, I'm very much a beginner and this is my first attempt with Unicode. Thanks, Doori Bar #include <stdio.h> #include <stdlib.h> #include <wchar.h> #include <string.h> #include <errno.h> void *error_malloc(int size); void ansi_string(char **str1, char **str2); void unicode_string(wchar_t **wstr1, wchar_t **wstr2); void unicode_string(wchar_t **wstr1, wchar_t **wstr2) { /* assign wstr1 with the path: \\?\c:\Français\ */ *wstr1 = error_malloc((wcslen(L"\\\\?\\c:\\Français\\")+1) *sizeof(**wstr1)); wcscpy(*wstr1,L"\\\\?\\c:\\Français\\"); /* concat wstr1+"*" , assign wstr2 with: \\?\c:\Français\* */ *wstr2 = error_malloc((wcslen(*wstr1) + 1 + 1) * sizeof(**wstr1)); /* swprintf(*wstr2,"%ls*",*wstr1); */ /* how should I concat wstr1+"*"? */ wcscpy(*wstr2,L"\\\\?\\c:\\Français\\"); } void ansi_string(char **str1, char **str2) { /* assign str1 with the path: c:\English\ */ *str1 = error_malloc(strlen("c:\\English\\") + 1); strcpy(*str1,"c:\\English\\"); /* concat str1+"*" , assign str2 with: c:\English\* */ *str2 = error_malloc(strlen(*str1) + 1 + 1); sprintf(*str2,"%s*",*str1); } void *error_malloc(int size) { void *ptr; int errornumber; if ((ptr = malloc(size)) == NULL) { errornumber = errno; fprintf(stderr,"Error: malloc(): %d; Error Message: %s;\n", errornumber,strerror(errornumber)); exit(1); } return ptr; } int main(void) { FILE *outfile; char *str1; char *str2; wchar_t *wstr1; wchar_t *wstr2; if ((outfile = fopen("out.bin","w")) == NULL) { printf("Error: fopen failed."); return 1; } ansi_string(&str1,&str2); fwrite(str2, sizeof(*str2), strlen(str2), outfile); printf("strlen: %d\n",strlen(str2)); printf("sizeof: %d\n",sizeof(*str2)); free(str1); free(str2); unicode_string(&wstr1,&wstr2); fwrite(wstr2, sizeof(*wstr2), wcslen(wstr2), outfile); printf("wcslen: %d\n",wcslen(wstr2)); printf("sizeof: %d\n",sizeof(*wstr2)); free(wstr1); free(wstr2); fclose(outfile); return 0; }

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  • How do I solve an unresolved external when using C++ Builder packages?

    - by David M
    I'm experimenting with reconfiguring my application to make heaving use of packages. Both I and another developer running a similar experiment are running into a bit of trouble when linking using several different packages. We're probably both doing something wrong, but goodness knows what :) The situation is this: The first package, PackageA.bpl, contains C++ class FooA. The class is declared with the PACKAGE directive. The second package, PackageB.bpl, contains a class inheriting from FooA, called FooB. It includes FooB.h, and the package is built using runtime packages, and links to PackageA by adding a reference to PackageA.bpi. When building PackageB, it compiles fine but linking fails with a number of unresolved externals, the first few of which are: [ILINK32 Error] Error: Unresolved external '__tpdsc__ FooA' referenced from C:\blah\FooB.OBJ [ILINK32 Error] Error: Unresolved external 'FooA::' referenced from C:\blah\FooB.OBJ [ILINK32 Error] Error: Unresolved external '__fastcall FooA::~FooA()' referenced from blah\FooB.OBJ etc. Running TDump on PackageA.bpl shows: Exports from PackageA.bpl 14 exported name(s), 14 export addresse(s). Ordinal base is 1. Sorted by Name: RVA Ord. Hint Name -------- ---- ---- ---- 00002A0C 8 0000 __tpdsc__ FooA 00002AD8 10 0001 __linkproc__ FooA::Finalize 00002AC8 9 0002 __linkproc__ FooA::Initialize 00002E4C 12 0003 __linkproc__ PackageA::Finalize 00002E3C 11 0004 __linkproc__ PackageA::Initialize 00006510 14 0007 FooA:: 00002860 5 0008 FooA::FooA(FooA&) 000027E4 4 0009 FooA::FooA() 00002770 3 000A __fastcall FooA::~FooA() 000028DC 6 000B __fastcall FooA::Method1() const 000028F4 7 000C __fastcall FooA::Method2() const 00001375 2 000D Finalize 00001368 1 000E Initialize 0000610C 13 000F ___CPPdebugHook So the class definitely seems to be exported and available to link. I can see entries for the specific things ILink32 says it's looking for and not finding. Running TDump on the BPI file shows similar entries. Other info The class does descend from TObject, though originally before refactoring into packages it was a normal C++ class. (More detail below. It seems "safer" using VCL-style classes when trying to solve problems with a very Delphi-ish thing like this anyway. Changing this only changes the order of unresolved externals to first not find Method1 and Method2, then others.) Declaration for FooA: class PACKAGE FooA: public TObject { public: FooA(); virtual __fastcall ~FooA(); FooA(const FooA&); virtual __fastcall long Method1() const; virtual __fastcall long Method2() const; }; and FooB: class FooB: public FooA { public: FooB(); virtual __fastcall ~FooB(); ... other methods... }; All methods definitely are implemented in the .cpp files, so it's not not finding them because they don't exist! The .cpp files also contain #pragma package(smart_init) near the top, under the includes. Questions that might help... Are packages reliable using C++, or are they only useable with Delphi code? Is linking to the first package by adding a reference to its BPI correct - is that how you're supposed to do it? I could use a LIB but it seems to make the second package much larger, and I suspect it's statically linking in the contents of the first. Can we use the PACKAGE directive only on TObject-derived classes? There is no compiler warning using it on standard C++ classes. Is splitting code into packages the best way to achieve the goal of isolating code and communicating through defined layers / interfaces? I've been investigating this path because it seems to be the C++Builder / Delphi Way, and if it worked it looks attractive. But are there better alternatives? I'm very new to using packages and have only known about them through using components before. Any general words of advice would be great! We're using C++Builder 2010. I've fabricated the class and method names in the above code examples, but other than that the details are exactly what we're seeing. Cheers, David

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  • Using undefined type.

    - by Knowing me knowing you
    //file list.h #include "stdafx.h" namespace st { struct My_List; typedef My_List list; list* create(const char* name); } //file list.cpp #include "stdafx.h" #include "list.h" namespace st { struct My_List { const char* name_; My_List* left_; My_List* right_; My_List(const char* name):name_(name), left_(nullptr), right_(nullptr) {} My_List(const My_List&); ~My_List() { } void insert(My_List*); void set_name(char* name) { name_ = name; } const char* get_name()const { return name_; } }; typedef My_List list; /*helper class for optor+ */ struct MyChar { const char* my_data_; MyChar(const char* c_string):my_data_(c_string){} operator const char*() { return my_data_; } operator char*() { return const_cast<char*>(my_data_); } }; char* operator+(MyChar left_, MyChar right_) { if (!left_.my_data_ || !right_.my_data_) { return 0; } size_t size = 1;//size is set to one for final '\0' char in an array char* p = "";//if both c_strings are empty this is returned bool has_left_ = false; bool has_right_ = false; if (strlen(left_)) { size += strlen(left_); has_left_ = true; } if (strlen(right_)) { size += strlen(right_); has_right_ = true; } bool both = has_left_ && has_right_ ? true : false; if (both) { p = new char[size](); const void* p_v = p;//just to keep address of beginning of p const char* tmp = left_; /*copying first c_string*/ while (*p++ = *tmp++); tmp = right_; /*one too far after last loop*/ --p; while (*p++ = *tmp++); *p = '\0'; /*go back to the beginning of an array*/ p = static_cast<char*>(const_cast<void*>(p_v)); return p; } else if (has_left_) { return left_; } else if (has_right_) { return right_; } return p;//returns "" if both c_strings were empty } My_List::My_List(const My_List& pat):left_(nullptr),right_(nullptr) { name_ = pat.name_ + MyChar("_cpy"); My_List* pattern = const_cast<My_List*>(&pat); My_List* target = this; while (pattern->right_) { target->right_ = static_cast<My_List*>(malloc(sizeof(My_List))); *target->right_ = *pattern->right_; target->right_->set_name(pattern->right_->get_name() + MyChar("_cpy")); target->right_->left_ = static_cast<My_List*>(malloc(sizeof(My_List))); *target->right_->left_ = *pattern->right_->left_; target->right_->left_->set_name(pattern->right_->left_->get_name() + MyChar("_cpy")); pattern = pattern->right_; target = target->right_; } } void My_List::insert(My_List* obj) { /*to catch first branch*/ My_List* tmp = this; if (tmp->right_) { /*go to the end of right side*/ while (tmp->right_) { tmp = tmp->right_; } tmp->right_ = obj; obj->left_ = tmp; } else { tmp->right_ = obj; obj->left_= this; } } My_List* create(const char* name) { return new My_List(name); } } //file main.cpp #include "stdafx.h" #include "list.h" using namespace st; int _tmain(int argc, _TCHAR* argv[]) { list* my = create("a"); list* b = create("b"); my->insert(b);//HERE I'M GETTING ERROR return 0; } err msg: 'Error 1 error C2027: use of undefined type 'st::My_List' 13' Why? Especially that if I comment this line it will get compiled and create() is using this type.

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  • Bewildering SegFault involving STL sort algorithm.

    - by just_wes
    Hello everybody, I am completely perplexed at a seg fault that I seem to be creating. I have: vector<unsigned int> words; and global variable string input; I define my custom compare function: bool wordncompare(unsigned int f, unsigned int s) { int n = k; while (((f < input.size()) && (s < input.size())) && (input[f] == input[s])) { if ((input[f] == ' ') && (--n == 0)) { return false; } f++; s++; } return true; } When I run the code: sort(words.begin(), words.end()); The program exits smoothly. However, when I run the code: sort(words.begin(), words.end(), wordncompare); I generate a SegFault deep within the STL. The GDB back-trace code looks like this: #0 0x00007ffff7b79893 in std::string::size() const () from /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.4/libstdc++.so.6 #1 0x0000000000400f3f in wordncompare (f=90, s=0) at text_gen2.cpp:40 #2 0x000000000040188d in std::__unguarded_linear_insert<__gnu_cxx::__normal_iterator<unsigned int*, std::vector<unsigned int, std::allocator<unsigned int> > >, unsigned int, bool (*)(unsigned int, unsigned int)> (__last=..., __val=90, __comp=0x400edc <wordncompare(unsigned int, unsigned int)>) at /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.4/include/g++-v4/bits/stl_algo.h:1735 #3 0x00000000004018df in std::__unguarded_insertion_sort<__gnu_cxx::__normal_iterator<unsigned int*, std::vector<unsigned int, std::allocator<unsigned int> > >, bool (*)(unsigned int, unsigned int)> (__first=..., __last=..., __comp=0x400edc <wordncompare(unsigned int, unsigned int)>) at /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.4/include/g++-v4/bits/stl_algo.h:1812 #4 0x0000000000402562 in std::__final_insertion_sort<__gnu_cxx::__normal_iterator<unsigned int*, std::vector<unsigned int, std::allocator<unsigned int> > >, bool (*)(unsigned int, unsigned int)> (__first=..., __last=..., __comp=0x400edc <wordncompare(unsigned int, unsigned int)>) at /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.4/include/g++-v4/bits/stl_algo.h:1845 #5 0x0000000000402c20 in std::sort<__gnu_cxx::__normal_iterator<unsigned int*, std::vector<unsigned int, std::allocator<unsigned int> > >, bool (*)(unsigned int, unsigned int)> (__first=..., __last=..., __comp=0x400edc <wordncompare(unsigned int, unsigned int)>) at /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.4/include/g++-v4/bits/stl_algo.h:4822 #6 0x00000000004012d2 in main (argc=1, args=0x7fffffffe0b8) at text_gen2.cpp:70 I have similar code in another program, but in that program I am using a vector instead of vector. For the life of me I can't figure out what I'm doing wrong. Thanks!

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  • Why isn't this javascript with else if working?

    - by Uni
    I'm sorry I can't be any more specific - I have no idea where the problem is. I'm a total beginner, and I've added everything I know to add to the coding, but nothing happens when I push the button. I don't know at this point if it's an error in the coding, or a syntax error that makes it not work. Basically I am trying to get this function "Rip It" to go through the list of Dewey decimal numbers, change some of them, and return the new number and a message saying it's been changed. There is also one labeled "no number" that has to return an error (not necessarily an alert box, a message in the same space is okay.) I am a total beginner and not particularly good at this stuff, so please be gentle! Many thanks! <!DOCTYPE html> <html> <head> <script type="text/javascript"> function RipIt() { for (var i = l; i <=10 i=i+l) { var dewey=document.getElementById(i); dewey=parseFloat(dewey); if (dewey >= 100 && 200 >= dewey) { document.getElementById('dewey'+ 100) } else if (dewey >= 400 && 500 >= dewey) { document.getElementById('dewey'+ 200) } else if (dewey >= 850 && 900 >= dewey) { document.getElementById('dewey'-100) } else if (dewey >= 600 && 650 >= dewey) { document.getElementById('dewey'+17) } } } </script> </head> <body> <h4>Records to Change</h4> <ul id="myList"> <li id ="1">101.33</li> <li id = "2">600.01</li> <li id = "3">001.11</li> <li id = "4">050.02</li> <li id = "5">199.52</li> <li id = "6">400.27</li> <li id = "7">401.73</li> <li id = "8">404.98</li> <li id = "9">no number</li> <li id = "10">850.68</li> <li id = "11">853.88</li> <li id = "12">407.8</li> <li id = "13">878.22</li> <li id = "14">175.93</li> <li id = "15">175.9</li> <li id = "16">176.11</li> <li id = "17">190.97</li> <li id = "18">90.01</li> <li id = "19">191.001</li> <li id = "20">600.95</li> <li id = "21">602.81</li> <li id = "22">604.14</li> <li id = "23">701.31</li> <li id = "24">606.44</li> <li id = "25">141.77</li> </ul> <b> </b> <input type="button" value="Click To Run" onclick="RipIt()"> <!-- <input type="button" value="Click Here" onClick="showAlert();"> --> </body> </html>

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  • add the same qtreewidgetitems into the second column

    - by srinu
    hello i am using the following program to display the qtreewidget. main.cpp include include "qdomsimple.h" include include "qdomsimple.h" int main(int argc, char *argv[]) { QApplication a(argc, argv); QStringList filelist; filelist.push_back("C:\department1.xml"); filelist.push_back("C:\department2.xml"); filelist.push_back("C:\department3.xml"); QDOMSimple w(filelist); w.resize(260,200); w.show(); return a.exec(); } qdomsimple.cpp include "qdomsimple.h" include include QDOMSimple::QDOMSimple(QStringList strlst,QWidget *parent) : QWidget(parent) { k=0; // DOM document QDomDocument doc("title"); QStringList headerlabels; headerlabels.push_back("Chemistry"); headerlabels.push_back("Mechanical"); headerlabels.push_back("IT"); m_tree = new QTreeWidget( this ); m_tree->setColumnCount(3); m_tree->setHeaderLabels(headerlabels); QStringList::iterator it; for(it=strlst.begin();it<strlst.end();it++) { QFile file(*it); if ( file.open( QIODevice::ReadOnly | QIODevice::Text )) { // The tree view to be filled with xml data // (m_tree is a class member variable) // Creating the DOM tree doc.setContent( &file ); file.close(); // Root of the document QDomElement root = doc.documentElement(); // Taking the first child node of the root QDomNode child = root.firstChild(); // Setting the root as the header of the tree //QTreeWidgetItem* header = new QTreeWidgetItem; //header->setText(k,root.nodeName()); //m_tree->setHeaderItem(header); // Parse until the end of document while (!child.isNull()) { //Convert a DOM node to DOM element QDomElement element = child.toElement(); //Parse only if the node is a really an element if (!element.isNull()) { //Parse the element recursively parseElement( element,0); //Go to the next sibling child = child.nextSiblingElement(); } } //m_tree->setGeometry( QApplication::desktop()->availableGeometry() ); //setGeometry( QApplication::desktop()->availableGeometry() ); } k++; } } void QDOMSimple::parseElement( QDomElement& aElement, QTreeWidgetItem *aParentItem ) { // A map of all attributes of an element QDomNamedNodeMap attrMap = aElement.attributes(); // List all attributes QStringList attrList; for ( int i = 0; i < attrMap.count(); i++ ) { // Attribute name //QString attr = attrMap.item( i ).nodeName(); //attr.append( "-" ); /* Attribute value QString attr; attr.append( attrMap.item( i ).nodeValue() );*/ //attrList.append( attr ); attrList.append(attrMap.item( i).nodeValue()); } QTreeWidgetItem* item; // Create a new view item for elements having child nodes if (aParentItem) { item = new QTreeWidgetItem(aParentItem); } // Create a new view item for elements without child nodes else { item = new QTreeWidgetItem( m_tree ); } //Set tag name and the text QString tagNText; tagNText.append( aElement.tagName() ); //tagNText.append( "------" ); //tagNText.append( aElement.text() ); item->setText(0, tagNText ); // Append attributes to the element node of the tree for ( int i = 0; i < attrList.count(); i++ ) { QTreeWidgetItem* attrItem = new QTreeWidgetItem( item ); attrItem->setText(0, attrList[i] ); } // Repeat the process recursively for child elements QDomElement child = aElement.firstChildElement(); while (!child.isNull()) { parseElement( child, item ); child = child.nextSiblingElement(); } } QDOMSimple::~QDOMSimple() { } for this i got the qtreewidget like this +file1 +file2 +file3 but actual wanted output is +file1 +file2 +file3 i don't know how to do it.Thanks in advance

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  • STL vector reserve() and copy()

    - by natersoz
    Greetings, I am trying to perform a copy from one vector (vec1) to another vector (vec2) using the following 2 abbreviated lines of code (full test app follows): vec2.reserve( vec1.size() ); copy(vec1.begin(), vec1.end(), vec2.begin()); While the call to vec2 sets the capacity of vector vec2, the copying of data to vec2 seems to not fill in the values from vec1 to vec2. Replacing the copy() function with calls to push_back() works as expected. What am I missing here? Thanks for your help. vectest.cpp test program followed by resulting output follows. Compiler: gcc 3.4.4 on cygwin. Nat /** * vectest.cpp */ #include <iostream> #include <vector> using namespace std; int main() { vector<int> vec1; vector<int> vec2; vec1.push_back(1); vec1.push_back(2); vec1.push_back(3); vec1.push_back(4); vec1.push_back(5); vec1.push_back(6); vec1.push_back(7); vec2.reserve( vec1.size() ); copy(vec1.begin(), vec1.end(), vec2.begin()); cout << "vec1.size() = " << vec1.size() << endl; cout << "vec1.capacity() = " << vec1.capacity() << endl; cout << "vec1: "; for( vector<int>::const_iterator iter = vec1.begin(); iter < vec1.end(); ++iter ) { cout << *iter << " "; } cout << endl; cout << "vec2.size() = " << vec2.size() << endl; cout << "vec2.capacity() = " << vec2.capacity() << endl; cout << "vec2: "; for( vector<int>::const_iterator iter = vec2.begin(); iter < vec2.end(); ++iter ) { cout << *iter << endl; } cout << endl; } output: vec1.size() = 7 vec1.capacity() = 8 vec1: 1 2 3 4 5 6 7 vec2.size() = 0 vec2.capacity() = 7 vec2:

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  • C++ template function specialization using TCHAR on Visual Studio 2005

    - by Eli
    I'm writing a logging class that uses a templatized operator<< function. I'm specializing the template function on wide-character string so that I can do some wide-to-narrow translation before writing the log message. I can't get TCHAR to work properly - it doesn't use the specialization. Ideas? Here's the pertinent code: // Log.h header class Log { public: template <typename T> Log& operator<<( const T& x ); template <typename T> Log& operator<<( const T* x ); template <typename T> Log& operator<<( const T*& x ); ... } template <typename T> Log& Log::operator<<( const T& input ) { printf("ref"); } template <typename T> Log& Log::operator<<( const T* input ) { printf("ptr"); } template <> Log& Log::operator<<( const std::wstring& input ); template <> Log& Log::operator<<( const wchar_t* input ); And the source file // Log.cpp template <> Log& Log::operator<<( const std::wstring& input ) { printf("wstring ref"); } template <> Log& Log::operator<<( const wchar_t* input ) { printf("wchar_t ptr"); } template <> Log& Log::operator<<( const TCHAR*& input ) { printf("tchar ptr ref"); } Now, I use the following test program to exercise these functions // main.cpp - test program int main() { Log log; log << "test 1"; log << L"test 2"; std::string test3( "test3" ); log << test3; std::wstring test4( L"test4" ); log << test4; TCHAR* test5 = L"test5"; log << test4; } Running the above tests reveals the following: // Test results ptr wchar_t ptr ref wstring ref ref Unfortunately, that's not quite right. I'd really like the last one to be "TCHAR", so that I can convert it. According to Visual Studio's debugger, the when I step in to the function being called in test 5, the type is wchar_t*& - but it's not calling the appropriate specialization. Ideas? I'm not sure if it's pertinent or not, but this is on a Windows CE 5.0 device.

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  • Constructor ambiguous quesiton

    - by Crystal
    I'm trying to create a simple date class, but I get an error on my main file that says, "call of overloaded Date() is ambiguous." I'm not sure why since I thought as long as I had different parameters for my constructor, I was ok. Here is my code: header file: #ifndef DATE_H #define DATE_H using std::string; class Date { public: static const int monthsPerYear = 12; // num of months in a yr Date(int = 1, int = 1, int = 1900); // default constructor Date(); // uses system time to create object void print() const; // print date in month/day/year format ~Date(); // provided to confirm destruction order string getMonth(int month) const; // gets month in text format private: int month; // 1 - 12 int day; // 1 - 31 int year; // any year int checkDay(int) const; }; #endif .cpp file #include <iostream> #include <iomanip> #include <string> #include <ctime> #include "Date.h" using namespace std; Date::Date() { time_t seconds = time(NULL); struct tm* t = localtime(&seconds); month = t->tm_mon; day = t->tm_mday; year = t->tm_year; } Date::Date(int mn, int dy, int yr) { if (mn > 0 && mn <= monthsPerYear) month = mn; else { month = 1; // invalid month set to 1 cout << "Invalid month (" << mn << ") set to 1.\n"; } year = yr; // could validate yr day = checkDay(dy); // validate the day // output Date object to show when its constructor is called cout << "Date object constructor for date "; print(); cout << endl; } void Date::print() const { string str; cout << month << '/' << day << '/' << year << '\n'; // new code for HW2 cout << setfill('0') << setw(3) << day; // prints in ddd cout << " " << year << '\n'; // yyyy format str = getMonth(month); // prints in month (full word), day, year cout << str << " " << day << ", " << year << '\n'; } and my main.cpp #include <iostream> #include "Date.h" using std::cout; int main() { Date date1(4, 30, 1980); date1.print(); cout << '\n'; Date date2; date2.print(); }

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  • Using LINQ to create a simple login

    - by JDWebs
    I'm an C# ASP.NET beginner, so please excuse anything that's... not quite right! In short, I want to create a really basic login system: one which runs through a database and uses sessions so that only logged in users can access certain pages. I know how to do most of that, but I'm stuck with querying data with LINQ on the login page. On the login page, I have a DropDownList to select a username, a Textbox to type in a password and a button to login (I also have a literal for errors). The DropDownList is databound to a datatable called DT_Test. DT_Test contains three columns: UsernameID (int), Username (nchar(30)) and Password (nchar(30)). UsernameID is the primary key. I want to make the button's click event query data from the database with the DropDownList and Textbox, in order to check if the username and password match. But I don't know how to do this... Current Code (not a lot!): Front End: <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Login_Test.aspx.cs" Inherits="Login_Login_Test" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <title>Login Test</title> </head> <body> <form id="LoginTest" runat="server"> <div> <asp:DropDownList ID="DDL_Username" runat="server" Height="20px" DataTextField="txt"> </asp:DropDownList> <br /> <asp:TextBox ID="TB_Password" runat="server" TextMode="Password"></asp:TextBox> <br /> <asp:Button ID="B_Login" runat="server" onclick="B_Login_Click" Text="Login" /> <br /> <asp:Literal ID="LI_Result" runat="server"></asp:Literal> </div> </form> </body> </html> Back End: using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; public partial class Login_Login_Test : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { if (!Page.IsPostBack) { Binder(); } } private void Binder() { using (DataClassesDataContext db = new DataClassesDataContext()) { DDL_Username.DataSource = from x in db.DT_Honeys select new { x.UsernameID, txt = x.Username }; DDL_Username.DataBind(); } } protected void B_Login_Click(object sender, EventArgs e) { if (TB_Password.Text != "") { using (DataClassesDataContext db = new DataClassesDataContext()) { } } } } I have spent hours searching and trying different code, but none of it seems to fit in for this context. Anyway, help and tips appreciated, thank you very much! I am aware of security risks etc. but this is not a live website or anything, it is simply for testing purposes as a beginner. *

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  • C++ std::vector insert segfault

    - by ArunSaha
    I am writing a test program to understand vector's better. In one of the scenarios, I am trying to insert a value into the vector at a specified position. The code compiles clean. However, on execution, it is throwing a Segmentation Fault from the v8.insert(..) line (see code below). I am confused. Can somebody point me to what is wrong in my code? #define UNIT_TEST(x) assert(x) #define ENSURE(x) assert(x) #include <vector> typedef std::vector< int > intVector; typedef std::vector< int >::iterator intVectorIterator; typedef std::vector< int >::const_iterator intVectorConstIterator; intVectorIterator find( intVector v, int key ); void test_insert(); intVectorIterator find( intVector v, int key ) { for( intVectorIterator it = v.begin(); it != v.end(); ++it ) { if( *it == key ) { return it; } } return v.end(); } void test_insert() { const int values[] = {10, 20, 30, 40, 50}; const size_t valuesLength = sizeof( values ) / sizeof( values[ 0 ] ); size_t index = 0; const int insertValue = 5; intVector v8; for( index = 0; index < valuesLength; ++index ) { v8.push_back( values[ index ] ); } ENSURE( v8.size() == valuesLength ); for( index = 0; index < valuesLength; ++index ) { printf( "index = %u\n", index ); intVectorIterator it = find( v8, values[ index ] ); ENSURE( it != v8.end() ); ENSURE( *it == values[ index ] ); // intVectorIterator itToInsertedItem = v8.insert( it, insertValue ); // line 51 // UNIT_TEST( *itToInsertedItem == insertValue ); } } int main() { test_insert(); return 0; } $ ./a.out index = 0 Segmentation Fault (core dumped) (gdb) bt #0 0xff3a03ec in memmove () from /platform/SUNW,T5140/lib/libc_psr.so.1 #1 0x00012064 in std::__copy_move_backward<false, true, std::random_access_iterator_tag>::__copy_move_b<int> (__first=0x23e48, __last=0x23450, __result=0x23454) at /local/gcc/4.4.1/lib/gcc/sparc-sun-solaris2.10/4.4.1/../../../../include/c++/4.4.1/bits/stl_algobase.h:575 #2 0x00011f08 in std::__copy_move_backward_a<false, int*, int*> (__first=0x23e48, __last=0x23450, __result=0x23454) at /local/gcc/4.4.1/lib/gcc/sparc-sun-solaris2.10/4.4.1/../../../../include/c++/4.4.1/bits/stl_algobase.h:595 #3 0x00011d00 in std::__copy_move_backward_a2<false, int*, int*> (__first=0x23e48, __last=0x23450, __result=0x23454) at /local/gcc/4.4.1/lib/gcc/sparc-sun-solaris2.10/4.4.1/../../../../include/c++/4.4.1/bits/stl_algobase.h:605 #4 0x000119b8 in std::copy_backward<int*, int*> (__first=0x23e48, __last=0x23450, __result=0x23454) at /local/gcc/4.4.1/lib/gcc/sparc-sun-solaris2.10/4.4.1/../../../../include/c++/4.4.1/bits/stl_algobase.h:640 #5 0x000113ac in std::vector<int, std::allocator<int> >::_M_insert_aux (this=0xffbfeba0, __position=..., __x=@0xffbfebac) at /local/gcc/4.4.1/lib/gcc/sparc-sun-solaris2.10/4.4.1/../../../../include/c++/4.4.1/bits/vector.tcc:308 #6 0x00011120 in std::vector<int, std::allocator<int> >::insert (this=0xffbfeba0, __position=..., __x=@0xffbfebac) at /local/gcc/4.4.1/lib/gcc/sparc-sun-solaris2.10/4.4.1/../../../../include/c++/4.4.1/bits/vector.tcc:126 #7 0x00010bc0 in test_insert () at vector_insert_test.cpp:51 #8 0x00010c48 in main () at vector_insert_test.cpp:58 (gdb) q

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  • Error inserting data in binary tree

    - by chepe263
    I copied this code (in spanish) http://www.elrincondelc.com/nuevorincon/index.php?pag=codigos&id=4 and wrote a new one. This is my code: #include <cstdlib> #include <conio.h> #include <iostream> using namespace std; struct nodoarbol { int dato; struct nodoarbol *izq; struct nodoarbol *der; }; typedef nodoarbol Nodo; typedef Nodo *Arbol; void insertar(Arbol *, int); void inorden(Arbol); void postorden(Arbol); void preorden(Arbol); void insertar(Arbol *raiz, int nuevo){ if (*raiz==NULL){ *raiz = (Nodo *)malloc(sizeof(Nodo)); if (*raiz != NULL){ (*raiz)->dato=nuevo; (*raiz)->der=NULL; (*raiz)->izq=NULL; } else{ cout<<"No hay memoria suficiente u ocurrio un error"; } } else{ if (nuevo < (*raiz)->dato) insertar( &((*raiz)->izq), nuevo ); else if (nuevo > (*raiz)->dato) insertar(&((*raiz)->der), nuevo); } }//inseertar void inorden(Arbol raiz){ if (raiz != NULL){ inorden(raiz->izq); cout << raiz->dato << " "; inorden(raiz->der); } } void preorden(Arbol raiz){ if (raiz != NULL){ cout<< raiz->dato << " "; preorden(raiz->izq); preorden(raiz->der); } } void postorden(Arbol raiz){ if (raiz!=NULL){ postorden(raiz->izq); postorden(raiz->der); cout<<raiz->dato<<" "; } } int main() { int i; i=0; int val; Arbol raiz = NULL; for (i=0; i<10; i++){ cout<<"Inserte un numero"; cin>>val; insertar( (raiz), val); } cout<<"\nPreorden\n"; preorden(raiz); cout<<"\nIneorden\n"; inorden(raiz); cout<<"\nPostorden\n"; postorden(raiz); return 0; } I'm using netbeans 7.1.1, mingw32 compiler This is the output: make[2]: Leaving directory `/q/netbeans c++/NetBeansProjects/treek' make[1]: Leaving directory `/q/netbeans c++/NetBeansProjects/treek' main.cpp: In function 'int main()': main.cpp:110:30: error: cannot convert 'Arbol {aka nodoarbol*}' to 'Nodo** {aka nodoarbol**}' for argument '1' to 'void insertar(Nodo**, int)' make[2]: *** [build/Release/MinGW-Windows/main.o] Error 1 make[1]: *** [.build-conf] Error 2 make: *** [.build-impl] Error 2 BUILD FAILED (exit value 2, total time: 11s) I don't understand what's wrong since i just copied the code (and rewrite it to my own code). I'm really good in php, asp.net (vb) and other languages but c is a headche for me. I've been struggling with this problem for about an hour. Could somebody tell me what could it be?

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  • Ambiguous constructor call

    - by Crystal
    I'm trying to create a simple date class, but I get an error on my main file that says, "call of overloaded Date() is ambiguous." I'm not sure why since I thought as long as I had different parameters for my constructor, I was ok. Here is my code: header file: #ifndef DATE_H #define DATE_H using std::string; class Date { public: static const int monthsPerYear = 12; // num of months in a yr Date(int = 1, int = 1, int = 1900); // default constructor Date(); // uses system time to create object void print() const; // print date in month/day/year format ~Date(); // provided to confirm destruction order string getMonth(int month) const; // gets month in text format private: int month; // 1 - 12 int day; // 1 - 31 int year; // any year int checkDay(int) const; }; #endif .cpp file #include <iostream> #include <iomanip> #include <string> #include <ctime> #include "Date.h" using namespace std; Date::Date() { time_t seconds = time(NULL); struct tm* t = localtime(&seconds); month = t->tm_mon; day = t->tm_mday; year = t->tm_year; } Date::Date(int mn, int dy, int yr) { if (mn > 0 && mn <= monthsPerYear) month = mn; else { month = 1; // invalid month set to 1 cout << "Invalid month (" << mn << ") set to 1.\n"; } year = yr; // could validate yr day = checkDay(dy); // validate the day // output Date object to show when its constructor is called cout << "Date object constructor for date "; print(); cout << endl; } void Date::print() const { string str; cout << month << '/' << day << '/' << year << '\n'; // new code for HW2 cout << setfill('0') << setw(3) << day; // prints in ddd cout << " " << year << '\n'; // yyyy format str = getMonth(month); // prints in month (full word), day, year cout << str << " " << day << ", " << year << '\n'; } and my main.cpp #include <iostream> #include "Date.h" using std::cout; int main() { Date date1(4, 30, 1980); date1.print(); cout << '\n'; Date date2; date2.print(); }

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  • Do classes which have a vector has a member have memory issues

    - by user263766
    I am just starting out C++, so sorry if this is a dumb question. I have a class Braid whose members are vectors. I have not written an assignment operator. When I do a lot of assignments to an object of the type Braid, I run into memory issues :- 0 0xb7daff89 in _int_malloc () from /lib/libc.so.6 #1 0xb7db2583 in malloc () from /lib/libc.so.6 #2 0xb7f8ac59 in operator new(unsigned int) () from /usr/lib/libstdc++.so.6 #3 0x0804d05e in __gnu_cxx::new_allocator<int>::allocate (this=0xbf800204, __n=1) at /usr/lib/gcc/i686-pc-linux-gnu/4.4.3/../../../../include/c++/4.4.3/ext/new_allocator.h:89 #4 0x0804cb0e in std::_Vector_base<int, std::allocator<int> >::_M_allocate (this=0xbf800204, __n=1) at /usr/lib/gcc/i686-pc-linux-gnu/4.4.3/../../../../include/c++/4.4.3/bits/stl_vector.h:140 #5 0x0804c086 in _Vector_base (this=0xbf800204, __n=1, __a=...) at /usr/lib/gcc/i686-pc-linux-gnu/4.4.3/../../../../include/c++/4.4.3/bits/stl_vector.h:113 #6 0x0804b4b7 in vector (this=0xbf800204, __x=...) at /usr/lib/gcc/i686-pc-linux-gnu/4.4.3/../../../../include/c++/4.4.3/bits/stl_vector.h:242 #7 0x0804b234 in Braid (this=0xbf800204) at braid.h:13 #8 0x080495ed in Braid::cycleBraid (this=0xbf8001b4) at braid.cpp:191 #9 0x080497c6 in Braid::score (this=0xbf800298, b=...) at braid.cpp:251 #10 0x08049c46 in Braid::evaluateMove (this=0xbf800468, move=1, pos=0, depth=2, b=...) I suspect that these memory issues are because the vectors are getting resized. What I want to know is whether objects of type Braid automatically expand when its members expand? he code I am writing is really long so I will post the section which is causing the problems. Here is the relevant section of the code :- class Braid { private : vector<int> braid; //Stores the braid. int strands; vector < vector<bool> > history; vector < vector<bool> > CM; public : Braid () : strands(0) {} Braid operator * (Braid); Braid* inputBraid(int,vector<int>); int printBraid(); int printBraid(vector<vector<int>::iterator>); vector<int>::size_type size() const; ..... ..... } Here is the function which causes the issue :- int Braid::evaluateMove(int move,int pos,int depth,Braid b) { int netscore = 0; Braid curr(*this); curr = curr.move(move,pos); netscore += curr.score(b); while(depth > 1) { netscore += curr.evaluateMove(1,0,depth,b); netscore += curr.evaluateMove(2,0,depth,b); for(int i = 0; i < braid.size();++i) { netscore += curr.evaluateMove(3,i,depth,b); netscore += curr.evaluateMove(4,i,depth,b); netscore += curr.evaluateMove(5,i,depth,b); curr = curr.cycleBraid(); netscore += curr.evaluateMove(6,0,depth,b); } --depth; } return netscore; }

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  • Unable to install Eclipse manually

    - by veerendar
    I have just started Linux. I have a SBC(Atom processor) on which I have installed Ubuntu 12.04 and now I am trying to install Fortran IDE. For which I have learnt that I need to install OpenJDK first, then Eclipse Juno and at last the Phortran plugin for Eclipse. I have no Internet access so I had follow the below steps for manual installation. First download the eclipse tar.gz package (downloaded: eclipse-parallel-juno-linux-gtk.tar). Then right-click the eclipse tar.gz and choose the extract here option to extract the tar.gz package.You can also use the command line to extract the tar.gz package. # tar xzf eclipse-cpp-juno-linux-gtk.tar.gz Move to /opt/ folder. # mv eclipse /opt/ Use sudo if the above command gives permission denied message. # sudo mv eclipse /opt/ Create a desktop file and place it into /usr/share/applications # sudo gedit /usr/share/applications/eclipse.desktop and copy the following to the eclipse.desktop file [Desktop Entry] Name=Eclipse Type=Application Exec=/opt/eclipse/eclipse Terminal=false Icon=/opt/eclipse/icon.xpm Comment=Integrated Development Environment NoDisplay=false Categories=Development;IDE Name[en]=eclipse.desktop Create a symlink in /usr/local/bin using # cd /usr/local/bin # sudo ln -s /opt/eclipse/eclipse Now its the time to launch eclipse. # /opt/eclipse/eclipse -clean & Now at step 5, when I type the command sudo ln -s /opt/eclipse/eclipse , I get an this error message: ln: Failed to create symbolic link './eclipse': File exists. Please help me in resolving this.

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  • How to study for 70-573 Microsoft SharePoint 2010, Application Development

    - by ybbest
    I just passed my 70-573 exam today and would like to Share my experience on learning SharePoint 2010 as a beginner. 1. Book Microsoft SharePoint 2010: Building Solutions for SharePoint 2010 by Sahil Malik http://apress.com/book/view/1430228652 Sahil is an expert and MVP in SharePoint 2010.He certainly know his field and the book is well written. More importantly Sahil has got very good sense of humor in delivering the knowledge. 2.A development machine It is of great importance to have a dev machine , you cannot learn a new technology by just reading a book nor by watching some training videos. You need get your hands dirty with SharePoint a lot. 3.Training videos Since I have one year subscription with learndev , I use them as my learning resources. It is quite cheap , only cost US $99 for a year subscription and you will get not only the SharePoint training but the whole training library .The videos are from Appdev . Appdev training is of high quality. http://www.appdev.com/ http://www.learndevnow.com/ You can also get the videos from Microsoft SharePoint site. They are pretty good too. But bear in mind , by just watching these videos you will not learn much , you need to build a SharePoint 2010 machine and play with it .Try to write the sample code yourself and not just copy and paste. 4. Write blogs about your learning. This will motive you in your long journey with SharePoint learning. 5. Do check out the patterns & practices SharePoint Guidance on codeplex. http://spg.codeplex.com/ 6.Thanks for Becky Bertram,who kindly put up all the exam requirements with links to MSDN http://blog.beckybertram.com/Lists/Exam%2070573%20Study%20Guide/AllItems.aspx

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