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  • c++ Using const in a copy constructor?

    - by Anton
    I have never written copy constructor, so in order to avoid pain i wanted to know if what i have coded is legit. It compiles but i am not sure that it works as a copy constructor should. Also do i have to use const in the copy constructor or i can simply drop it. (What i dont like about const is that the compiler cries if i use some non const functions). //EditNode.h class EditNode { explicit EditNode(QString elementName); EditNode(const EditNode &src); } //EditNodeContainer.h class EditNodeContainer : public EditNode { explicit EditNodeContainer(QString elementName); EditNodeContainer(const EditNodeContainer &src); } //EditNodeContainer.cpp EditNodeContainer::EditNodeContainer(QString elementName):EditNode(elementName) { } //This seems to compile but not sure if it works EditNodeContainer::EditNodeContainer(const EditNodeContainer &src):EditNode(src) { } //the idea whould be to do something like this EditNodeContainer *container1 = new EditNodeContainer("c1"); EditNodeContainer *copyContainer = new EditNodeContainer(container1);

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  • Data loss between conversion

    - by Alex Brooks
    Why is it that I loose data between the conversions below even though both types take up the same amount of space? If the conversion was done bitwise, it should be true that x = z unless data is being stripped during the conversion, right? Is there a way to do the two conversions without losing data (i.e. so that x = z)? main.cpp: #include <stdio.h> #include <stdint.h> int main() { double x = 5.5; uint64_t y = static_cast<uint64_t>(x); double z = static_cast<double>(y) // Desire : z = 5.5; printf("Size of double: %lu\nSize of uint64_t: %lu\n", sizeof(double), sizeof(uint64_t)); printf("%f\n%lu\n%f\n", x, y, z); } Results: Size of double: 8 Size of uint64_t: 8 5.500000 5 5.000000

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  • Deciphering a queer compiler warning about unsigned decimal constant

    - by Artagnon
    This large application has a memory pool library which uses a treap internally to store nodes of memory. The treap is implemented using cpp macros, and the complete file trp.h can be found here. I get the following compiler warning when I attempt to compile the application: warning: this decimal constant is unsigned only in ISO C90 By deleting portions of the macro code and using trial-and-error, I finally found the culprit: #define trp_prio_get(a_type, a_field, a_node) \ (2654435761*(uint32_t)(uintptr_t)(a_node)) I'm not sure what that strange number is doing there, but I assume it's there for a good reason, so I just want to leave it alone. I do want to fix the warning though- any idea why the compiler's saying that it's unsigned only in ISO C90? EDIT: I'm using gcc-4.1

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  • What information about me and my system do compilers add to executeables?

    - by I can't tell you my name.
    I'm currently using Microsoft Visual Studio 2010. If we say that we give 10 different people a copy of MSVC 10 and a short C++ Hello, World listing. They all create a new project using exactly the same settings, add a new cpp file with the Hello, World program and compile it. Do they all get the exactly same binary? If not, what are the exact differences? What information about my system does MSVC add to my executeable? Paranoia!

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  • How do I compile for windows XP under windows 7 / visual studio 2008

    - by Jon Cage
    I'm running Windows 7 and Visual Studio 2008 Pro and trying to get my application to work on Windows XP SP3. It's a really minimal command line program so should have any ridiculous dependencies: // XPBuild.cpp : Defines the entry point for the console application. // #include "stdafx.h" int _tmain(int argc, _TCHAR* argv[]) { printf("Hello world"); getchar(); return 0; } I read somewhere that defining several constants such as WINVER should allow me to compile for other platforms. I've tried the added the following to my /D compiler options: ;WINVER=0x0501;_WIN32_WINNT 0x0501;NTDDI_VERSION=NTDDI_WINXP But that made no difference. When I run it on my Windows XP machine (actually running in a virtualbox) I get the following error: This application has failed to start because the application configuration is incorrect. Reinstalling the application may fix this problem. So what have I missed? Is there something else required to run MSVC compiled programs or a different compiler option or something else?

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  • Multiple constructors definitions with same name but different signatures (C++)

    - by PuRe_ChAoS12
    With the following code, I keep getting error C2535 when I compile. It's complaining that a member function already defined or declared. Rationnel.h ... class Rationnel { public: Rationnel(int); //Constructor Rationnel(int,int); //Constructor void add(const Rationnel); ... Rationnel.cpp ... //Constructor Rationnel::Rationnel(int n = 1) { numerateur = n; denominateur = 1; } //Constructor Rationnel::Rationnel(int n = 1, int d = 1) { numerateur = n; denominateur = d; } ... Any idea what could be causing the error? Thanks for your time.

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  • C++/CLI: CA2123: Requires SecurityCriticalAttribute?

    - by TomTom
    I am a little lost on erros like that: Warning 7 CA2123 : Microsoft.Security : Add the following security attribute to 'RithmicConnector::Connect(String^)' in order to match a LinkDemand on base method 'IConnector::Connect(String^)': 'SecurityCriticalAttribute'. c:\work\nettecture\tradex\source\tradex.connectivity.rithmic\rithmicconnector.cpp 52 Tradex.Connectivity.Rithmic Where do I add the SecurityCriticalAttribute? I tried on the header file - but the error does not disappear. I have one of those pretty much on every exposed method of a (managed C++) interface DLL. And I want CA to run through. How do I fix those? Regards

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  • Why do I get CA1811 when I call a private method from a public method in C++/CLI?

    - by brickner
    I've recently upgraded my project from Visual Studio 2008 to Visual Studio 2010. By enabling Code Analysis and building on Release, I'm getting warning CA1811: Avoid uncalled private code. I've managed to reduce the code to this: .h file: public ref class Foo { public: virtual System::String^ ToString() override; private: static System::String^ Bar(); }; .cpp file: String^ Foo::ToString() { return Bar(); } String^ Foo::Bar() { return "abc"; } The warning I get: CA1811 : Microsoft.Performance : 'Foo::Bar(void)' appears to have no upstream public or protected callers. It doesn't matter if Bar() is static or not. I've tried to reproduce it in C# but I can't. I can only reproduce it in C++/CLI. Why do I get this warning? Is this a Visual Studio 2010 bug?

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  • Using code generated by Py++ as a Python extension

    - by gotgenes
    I have a need to wrap an existing C++ library for use in Python. After reading through this answer on choosing an appropriate method to wrap C++ for use in Python, I decided to go with Py++. I walked through the tutorial for Py++, using the tutorial files, and I got the expected output in generated.cpp, but I haven't figured out what to do in order to actually use the generated code as an extension I can import in Python. I'm sure I have to compile the code, now, but with what? Am I supposed to use bjam?

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  • Avoid warning 'Unreferenced Formal Parameter'

    - by bdhar
    I have a super class like this: class Parent { public: virtual void Function(int param); }; void Parent::Function(int param) { std::cout << param << std::endl; } ..and a sub-class like this: class Child : public Parent { public: void Function(int param); }; void Child::Function(int param) { ;//Do nothing } When I compile the sub-class .cpp file, I get this error warning C4100: 'param' : unreferenced formal parameter As a practise, we used to treat warnings as errors. How to avoid the above warning? Thanks.

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  • consts and other animals

    - by bks
    Hello i have a cpp code wich i'm having trouble reading. a class B is defined now, i understand the first two lines, but the rest isn't clear enough. is the line "B const * pa2 = pa1" defines a const variable of type class B? if so, what does the next line do? B a2(2); B *pa1 = new B(a2); B const * pa2 = pa1; B const * const pa3 = pa2; also, i'm having trouble figuring out the difference between these two: char const *cst = “abc”; const int ci = 15; thank you

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  • how to test if a string is a valid UTF16 string?

    - by superb
    I am using mongodb and javascript to do some string processing. Now I got some error like: Sun May 23 07:42:20 Assertion failure JS_EncodeCharacters( _context , s , srclen , dst , &len) scripting/engine_spidermonkey.cpp 152 0x80f4f7e 0x80f8794 0x811525b 0x811a953 0x8119fc4 0x8111bc5 0x81b408e 0x81c4ee7 0x81b4a10 0x817a881 0x817a7d8 0x817a6e2 0x811e1bb 0x80a777b 0x80a8f8a 0xb7cb2455 0x80a37a1 mongodb-linux-i686-1.4.2/bin/mongo(_ZN5mongo12sayDbContextEPKc+0xfe) [0x80f4f7e] After doing some google, I find that JS_EncodeCharacters return false if the input is not a valid UTF16 string. (if spidermonkey is build with UTF-8 enabled) So I was wondering how to test if the input string if a proper UTF16 string? so I can skip such kind of string to avoid problem ... Thanks

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  • Div Background Image

    - by marskie
    i just wanted to put the 2nd grey image background on the bottom part of my body. Sorry for this kind of newbie question thank a lot for helping newbie like me.. #bgtop { background-image:url(images/bgtop.png); background-repeat: repeat-x; } #bgbottom { background:url(images/bgbottom.png) repeat-x bottom;} body { font: 100% Verdana, Arial, Helvetica, sans-serif; background: #ededed; margin: 0; / padding: 0; text-align: center; color: #000000; } #container { width: 80%; background: #FFFFFF; margin: 0 auto; border: 1px solid #000000; text-align: left; } #header { background: #DDDDDD; padding: 0 10px 0 20px; } #header h1 { margin: 0; padding: 10px 0; } #mainContent { padding: 0 20px; background: #FFFFFF; } #footer { padding: 0 10px; background:#DDDDDD; } #footer p { margin: 0; padding: 10px 0; } HTML <body> <div id="bgtop"> <div id="bgbottom"> <div id="container"> <div id="header"> <h1>Header</h1> <!-- end #header --></div> <div id="mainContent"> <h1> Main Content </h1> <p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Praesent aliquam, justo convallis luctus rutrum, erat nulla fermentum diam, at nonummy quam ante ac quam. Maecenas urna purus, fermentum id, molestie in, commodo porttitor, felis. Nam blandit quam ut lacus. Quisque ornare risus quis ligula. Phasellus tristique purus a augue condimentum adipiscing. Aenean sagittis. Etiam leo pede, rhoncus venenatis, tristique in, vulputate at, odio. Donec et ipsum et sapien vehicula nonummy. Suspendisse potenti. Fusce varius urna id quam. Sed neque mi, varius eget, tincidunt nec, suscipit id, libero. In eget purus. Vestibulum ut nisl. Donec eu mi sed turpis feugiat feugiat. Integer turpis arcu, pellentesque eget, cursus et, fermentum ut, sapien. Fusce metus mi, eleifend sollicitudin, molestie id, varius et, nibh. Donec nec libero.</p> <h2>H2 level heading </h2> <p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Praesent aliquam, justo convallis luctus rutrum, erat nulla fermentum diam, at nonummy quam ante ac quam. Maecenas urna purus, fermentum id, molestie in, commodo porttitor, felis. Nam blandit quam ut lacus. Quisque ornare risus quis ligula. Phasellus tristique purus a augue condimentum adipiscing. Aenean sagittis. Etiam leo pede, rhoncus venenatis, tristique in, vulputate at, odio.</p> <!-- end #mainContent --></div> <div id="footer"> <p>Footer</p> <!-- end #footer --></div> </div> </div> <!-- end #container --></div> </body> </html>

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  • Program-wide data, C++

    - by bobobobo
    I'd like to make program-wide data in a C++ program. The easiest way to do it in C# is just public static members. C#: public static class DataContainer { public static Object data1 ; public static Object data2 ; } In C++ you can do the same thing C++ global data way#1: class DataContainer { public: static Object data1 ; static Object data2 ; } ; Object DataContainer::data1 ; Object DataContainer::data2 ; However there's also extern C++ global data way #2: class DataContainer { public: Object data1 ; Object data2 ; } ; extern DataContainer * dataContainer ; // instantiate in .cpp file Which is better, or possibly another way which I haven't thought about?

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  • some verd problems in qt

    - by prabhakaran
    I am very new to qt, So whatever I facing is either errors or problems. Here goes some of them, 1)Just try to install it in VisualStudio, you will got enough for the day. 2)After you installed it as a separate qt(without embedding it inside visual studio).Open a c++ file in qt, = then you won't get any option to compile it. 3)Create a empty qt4 project like below #include<iostream> using namespace std; int main(int a,char * argv[]) { } Then build it, you will get a error like this C:\qt-greenhouse\Trolltech\Code_less_create_more\Trolltech\Code_less_create_more\Troll\4.6\qt\src\winmain/qtmain_win.cpp:131: undefined reference to `qMain(int, char**)' Can anybody clear any of these problems to me.

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  • How to call a method withgin a vector?

    - by Mike Dooley
    Hi! How do I call a method of an object which is stored within a vector? The following code fails... ClassA* class_derived_a = new ClassDerivedA; ClassA* class_another_a = new ClassAnotherDerivedA; vector<ClassA*> test_vector; test_vector.push_back(class_derived_a); test_vector.push_back(class_another_a); for (vector<ClassA*>::iterator it = test_vector.begin(); it != test_vector.end(); it++) it->printOutput(); The code retrieves the following error: test3.cpp:47: error: request for member ‘printOutput’ in ‘* it.__gnu_cxx::__normal_iterator<_Iterator, _Container::operator- with _Iterator = ClassA**, _Container = std::vector ’, which is of non-class type ‘ClassA*’ The problem seems to be it->printOutput(); but at the moment I don't know how to call the method properly, does anyone know? regards mikey

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  • <function> referenced from; symbol(s) not found.

    - by jfm429
    I have a piece of C code that is used from a C++ function. At the top of my C++ file I have the line: #include "prediction.h" In prediction.h I have this: #ifndef prediction #define prediction #include "structs.h" typedef struct { double estimation; double variance; } response; response runPrediction(int obs, location* positions, double* observations, int targets, location* targetPositions); #endif I also have prediction.c, which has: #include "prediction.h" response runPrediction(int obs, location* positions, double* observations, int targets, location* targetPositions) { // code here } Now, in my C++ file (which as I said includes prediction.h) I call that function, then compile (through Xcode) I get this error: "runPrediction(int, location*, double*, int, location*)", referenced from: mainFrame::respondTo(char*, int)in mainFrame.o ld: symbol(s) not found collect2: ld returned 1 exit status prediction.c is marked for compilation for the current target. I don't have any problems with other .cpp files not being compiled. Any thoughts here?

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  • the problem only happens when i try create a release...

    - by ace
    I'm sorry if im not presenting this right, but i trully cannot understand what the problem is. i have a project to hand in, a code of 600 lines defined within a main, .cpp, and header file. if i compile the project with just a debugger and no release, it's fine. when i create it with the release, the following error occurs, for every function!!! 1st error: |36|multiple definition of `countLines(int&, std::vector const&)'| 2nd error: |36|first defined here| if someone will allow me and i can send them the entire code, that would be awesome - i have to have this done within 3 hours.

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  • (Visual) C++ project dependency analysis

    - by polyglot
    I have a few large projects I am working on in my new place of work, which have a complicated set of statically linked library dependencies between them. The libs number around 40-50 and it's really hard to determine what the structure was initially meant to be, there isn't clear documentation on the full dependency map. What tools would anyone recommend to extract such data? Presumably, in the simplest manner, if did the following: define the set of paths which correspond to library units set all .cpp/.h files within those to belong to those compilation units capture the 1st order #include dependency tree One would have enough information to compose a map - refactor - and recompose the map, until one has created some order. I note that http://www.ndepend.com have something nice but that's exclusively .NET unfortunately. I read something about Doxygen being able accomplish some static dependency analysis with configuration; has anyone ever pressed it into service to accomplish such a task?

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  • Visual Studio: Link executable

    - by smerlin
    Lets say I have: a static library project called "LIB" a application project called "LIBAPP" a application project called "APP" a application project called "APPTEST" When i add "LIB" to LIBAPP Project Dependencies, Visual Studio automatically links "LIBAPP" against LIB. But when i add APP to APPTEST Project Dependencies, it doesnt. Since i am doing unit tests of APP's classes in APPTEST, i have to link against APP, therefore i am currently manually linking against all *.obj files of APP (hundreds...) Since i have to change the link targets of APPTEST everytime i add or remove a *.cpp file from APP, this isnt a nice solution. So is there a way to force Visual Studio to do this for me automatically, like it does when adding a static library Project Dependency ?

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  • How to tell the MinGW linker not to export all symbols?

    - by James R.
    Hello, I'm building a Windows dynamic library using the MinGW toolchain. To build this library I'm statically linking to other 2 which offer an API and I have a .def file where I wrote the only symbol I want to be exported in my library. The problem is that GCC is exporting all of the symbols including the ones from the libraries I'm linking to. Is there anyway to tell the linker just to export the symbols in the def file? I know there is the option --export-all-symbols but there seems not to be the opposite to it. Right now the last line of the build script has this structure: g++ -shared CXXFLAGS DEFINES INCLUDES -o library.dll library.cpp DEF_FILE \ OBJECT_FILES LIBS -Wl,--enable-stdcall-fixup EDIT: In the docs about the linker it says that --export-all-symbols is the default behavior and that it's disabled when you don't use that option explicitly if you provide a def file, except when it doesn't; the symbols in 3rd party libs are being exported anyway. EDIT: Adding the option --exclude-libs LIBS doesn't keep their symbols from being exported either.

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  • How to write own DLL in Visual Studio, C language (not C++)

    - by oneee
    Dear all, I'm trying to create my own DLL... I used wizzard in VS2008 to create template for DLL. This works fine and the dll builds successfully (Test.dll is created). BUT, when I rename the file from Test.cpp to Test.c (which I guess causes compilation in C-mode), solution rebuilds also successfully, but no .dll is created. The list of all created files follows: mt.dep BuildLog.htm vc90.idb Test.dll.embed.manifest Test.dll.intermediate.manifest Test.obj MySecondCFile.obj vc90.pdb Test.dll.embed.manifest.res For my purposes it's essential that the dll be in C not C++, while I already have a lot of code written in C, which does not compile as C++. Do you know, why .dll is not created? What should I do?

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  • static const double in c++

    - by Crystal
    Is this the proper way to use a static const variable? In my top level class (Shape) #ifndef SHAPE_H #define SHAPE_H class Shape { public: static const double pi; private: double originX; double originY; }; const double Shape::pi = 3.14159265; #endif And then later in a class that extends Shape, I use Shape::pi. I get a linker error. I moved the const double Shape::pi = 3.14... to the Shape.cpp file and my program then compiles. Why does that happen? thanks.

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  • Getting Assert to work in Visual C++ Unit Tests?

    - by garsh0p
    I'm using Visual Studio 2008's built in testing framework in my Visual C++ project. I'm adding a new Test Project, then a new Unit Test. However, I can't use any of the functions provided by Assert. Assert shows up in the Intellisense, but I can't do anything with it. I've done unit tests fine in Visual C#. Am I forgetting to do anything? EDIT: There isn't much code because everything I'm doing is auto-generated by Visual Studio 2008. Here are the steps I'm doing: File - New Project - Visual C++ - General - Empty Project Right click solution in Solution Explorer - Add - New Project... Visual C++ - Test - Test Project Open UnitTest1.cpp (auto-generated) Go to TestMethod1() From here, when I try to use the Assert class (like Assert.AreEqual), I can't do it. If I do the same in a Visual C# project, it works fine.

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