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  • XCode 5 says I got a duplicate, which I don't

    - by GoodMove
    The point is every time I try to run a C++ code in XCode 5 (the file s "File.cpp") xcode returns this: duplicate symbol _main ld: 1 duplicate symbol for architecture i386 clang: error: linker command failed with exit code 1 (use -v to see invocation) And it only returns the error, when I got the following function whatever it contains: int main() { } I checked the folder, which XCode points to (where it says the duplicates are placed), but didn't find anything though. What am I supposed to do??? #include "File.h" using namespace std; void func (void){ cout << "Hello World!" << endl; }

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  • how to avoid repeating code?

    - by helloWorld
    I have some technical question, I have repeating code in my work, and I want to get rid of it, so I know that in C++ it is not good idea to use macro, but instead I must use inline function, is it good idea to use this function as inline: list<Data>::iterator foo(int data){ if(dataExists(data)){ list<Data>::iterator i; for(i = Data.begin(); i != Data.end(); ++i){ if(i->getData() == data){ break; } return i; //here I have one more problem, what can I return if data doesn't exist? } I'm beginner, and I think that this function is very unsafe, can somebody please give me advice, how can I improve my code, thanks in advance P.S. what usually do You use to avoid repeating code?

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  • How to build a Main Menu screen

    - by flow overstack
    Good day (and happy New Year), I'm a beginner VB.Net programmer using VS 2008. I'm planning a new winform project whose main form should look more or less like this: MAIN MENU 1. DoSomething1 2. DoSomething2 3. DoSomething3 ... Please choose: [TextBox] The user can either choose from the Main Menu (by clicking an item) or enter the item number in the textbox. For example, if the user clicks DoSomething3 in the Main Menu (or alternatively enters 3 in the textbox), another form will be opened and hide the main form. What would be the best way to implement it? Specifically, I would like to know how I make so that choosing from the menu and entering a number in the textbox fire the same event. Any help or hints will be appreciated.

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  • Heap Error in C++

    - by BobAlmond
    Dear all, I'm a beginner programmer in C++. Recently, I'm working on image processing thing using C++. but I have some problem that I want to ask. Suppose I have some code as follow: for (int i=0;i<100000;i++) { int * a = new int[10000]; //do something delete [] a; } When I executed that code, I receive runtime error, Heap Error... Is there anything wrong with that code, I mean, can I allocate memory and release it in the same loop? Thanks in advance...

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  • AJAX in ASP.NET - How do I check a checkbox and have the action reflected in the database?

    - by hamlin11
    This is about as beginner as it gets regarding AJAX, but here it goes. I want to have one checkbox somewhere on an ASP.NET web form (ASPX). When the user clicks the checkbox, I want one of those spinning indicators to show. While that spinning indicator is showing, I want an update operation to occur in the database to reflect that the user has intended for that checkbox to be checked. update MyTable set CheckboxChecked = 1 Then, as soon as the update operation has occurred, I want that to be reflected in the checkbox by removing the spinning indicator and replacing it with the standard checked checkbox. I'm guessing this is done with an UpdatePanel and possibly an update statement followed by a looped call to a select statement... but I have never used AJAX before and have no idea how to go about it. Thanks!

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  • What web application is recommended when programming in Java for beginners?

    - by user1710260
    I am a beginner (almost no knowledge) to web applications. I have been programming in Java for about a year now. I have being doing some research on the different frameworks that are available and I want to find which one is right for me. From what I found: Play, Stripes, and Spring are good choices for beginners, but how can I compare these frameworks together. What is it that I need to look for when comparing them? My project that I am starting to work on is similar to an App Store. Basically an info site on different apps. Any advise will be appreciated.

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  • Client validate non-model bound checkbox while using MVC 2 jQuery Validation

    - by Justin Saraceno
    Have: Using ASP.NET MVC 2, DataAnnotationsModel based server validation, and client validation with jQuery. Anything in my model is validated perfectly on the client with jQuery based validation (jQuery.validate and MicrosoftMvcJQueryValidation.js). Need: Adding an additional HTML <input type="checkbox" id="terms" /> to my form. I need jQuery validation to require that this checkbox is checked AND somehow hook it in with whatever jQuery client script MVC is automagically controlling. Yes, I know it won't validate on the server side, but I don't need or want it to. Seems like it should be simple but I'm new to MVC, a total beginner at jQuery, and my searches have been coming up blank. Any help would be appreciated!

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  • C++: Where can I define the body for a private function?

    - by Martijn Courteaux
    Hi, I have a header like this (header guards not shown): class GameSystem { public: GameSystem(Game *pcGame); virtual ~GameSystem(); void Setup(); private: void InitGame(); void RunGame(); void ExitGame(); Game *m_pcGame; /* Properties */ int m_nWidth; int m_nHeight; int m_nFps; bool m_bFullscreen; }; Where can I define the body for InitGame(), RunGame() and ExitGame()? Can I define it in my .cpp file? If so, how? Or am I obliged to make their body in my .h file? I'm using Eclipse and I began typing: void GameSystem:: and then he doesn't suggest the private functions.

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  • Dynamic-linked DLL needs to share a global variable with its caller.

    - by Fabian Wickborn
    I have a static library libStatic that defines a global variable like this Header file libStatic/globals.h: extern int globvar; Code file libStatic/globals.cpp: int globvar = 42; The DLL libDynamic and the executable runner are using this global variable. Furtheron, libDynamic is linked at run-time into runner (via LoadLibrary(), GetProcAddress(), and the works...) I understand this will lead to globvar being created twice, once in the heap of runner and once in the heap of libDynamic, which is of course very undesirable. Is there a good away around this? How can I ensure that libDynamic and runner are using the same globvar?

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  • Creating a Pop up and setting its view state before it displays

    - by theringostarrs
    Hi, I am a beginner developer in Flex, and I have been using viewstates lately. I had a couple of custom popup titlewindow components that are initialized using: PopUpManager.createPopUp(this, ContentCreate, true); They both contain view states already, and are very similar so I wanted to combione them into one popup titlewindow and change view state on initialisation of the popup to either the Create version of the popup or the Update. I thought I was being smart haha, but I realized soon after refactoring my code that, I as far as I know I can't pass parameters to the popup to indicate which state I want, if it is created using the PopUpManager. Does anyone know how to pass parameters to the PopupManager, or create the ContentCreate component(TitleWindow) in mxml or code so I can specify the view state?

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  • using python,How to cut the wav file between certain time ranges??

    - by kaushik
    How to cut the wav file between certain time ranges from multiple wav files and paste the segments together in a single wav file in continous time ?? For this i thou of a way,to store the contents of the wav file in array form and cut the segments required from the array copy thm in another file and convert it back into wav formant. but i hav no idea how to code it in python as i am a beginner in it.. plz help...any alternative methods which serve the purpose are also welcome.. Quick reply,xpected plzz.. Thanks in advance..

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  • How should I get Xcode to link an iOS project that uses a C++ static library

    - by user1681572
    Using Xcode, I've written a Cocoa Touch static library, mainly in C++. It exposes a C interface for the benefit of Objective-C client code. I have a client iOS app that uses it, and everything works and runs as expected, except that I found I needed to include a minimal .cpp file in the client project to get the link to succeed. Otherwise I get C++-related unresolved symbols, e.g. operator new(unsigned long). The above hack is easy and effective, and so I guess I'm not breaking any laws, but is there a proper way to eliminate my linker errors?

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  • Call a non member funcion on an instance before is constructed.

    - by Tom
    Hi everyone. I'm writing a class, and this doubt came up. Is this undef. behaviour? On the other hand, I'm not sure its recommended, or if its a good practice. Is it one if I ensure no exceptions to be thrown in the init function? //c.h class C{ float vx,vy; friend void init(C& c); public: C(); ~C(); }; //c.cpp C::C() { init(*this); } void init(C& c) //throws() to ensure no exceptions ? { c.vx = 0; c.vy = 0; } Thanks in advance

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  • c++ compilation error

    - by clamp
    hello, i got a compile error which i do not understand. i have a h/cpp file combination that does not contain a class but just defines some utility functions. when i try to use a struct that is defined in another class i get the error: error C2027: use of undefined type so, stripped down to the problem, the h file looks like this namespace A { void foo(B::C::SStruct const & Var); } the definition of SStruct is in a class which is in another h-file, that is of course included. namespace B { Class C { struct SStruct { }; } } what am i missing here? thanks!

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  • Confusion regarding a function definition in C

    - by user34790
    I found this function definition void *func(void *param) { } Actually, I have a certain confusion regarding this function definition. What does void * mean in the return type of the function as well as the argument. I am a beginner in C. So please don't mind. Thank you void *func(void *param) { int s = (int)param; .... } Well looking at the above program which I found. I think it should have been int *s = (int *)param; isn't it? I am confused

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  • When convert a void pointer to a specific type pointer, which casting symbol is better, static_cast or reinterpret_cast?

    - by BugCreater
    A beginner question with poor English: Here I got a void* param and want to cast(or change) it to a specific type. But I don't know which "casting symbol" to use. Either**static_cast** and reinterpret_cast works. I want to know which one is better? which one does the Standard C++ recommend? typedef struct { int a; }A, *PA; int foo(void* a) // the real type of a is A* { A* pA = static_cast<A*>(a); // or A* pA = reinterpret_cast<A*>(a);? cout<<pA->a<<endl; return 0; } Here I use A* pA = static_cast(a); or A* pA = reinterpret_cast(a); is more proper?

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  • aligning extern constants (gcc)

    - by ~buratinas
    I want to make some static constants globally visible. I'm pretty familiar how to do that in C++. The problem is that these constants need to be aligned to some exotic boundary. Do I have to specify the alignment in extern declaration? I'm using GCC4.5 in *.cpp file static const constant_t constant __attribute__((aligned(64))) = {blah,blah,blah}; in *.h file //Which one is correct? extern const constant_t constant; extern const constant_t constant __attribute__((aligned(64)));

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  • Calling C++ function from C.

    - by claws
    I know this. Calling C function from C++: If my application was in C++ and I had to call functions from a library written in C. Then I would have used //main.cpp extern "C" void C_library_function(int x, int y);//prototype C_library_function(2,4);// directly using it. This wouldn't mangle the name C_library_function and linker would find the same name in its input *.lib files and problem is solved. Calling C++ function from C??? But here I'm extending a large application which is written in C and I need to use a library which is written in C++. Name mangling of C++ is causing trouble here. Well I cannot use C++ compiler over my C project because thats breaking lot of other stuff. What is the way out? By the way I'm using MSVC

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  • Call a non member function on an instance before is constructed.

    - by Tom
    Hi everyone. I'm writing a class, and this doubt came up. Is this undef. behaviour? On the other hand, I'm not sure its recommended, or if its a good practice. Is it one if I ensure no exceptions to be thrown in the init function? //c.h class C{ float vx,vy; friend void init(C& c); public: C(); }; //c.cpp C::C() { init(*this); } void init(C& c) //throws() to ensure no exceptions ? { c.vx = 0; c.vy = 0; } Thanks in advance

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  • jQuery Load MySQL Fetch Array

    - by Robert Hanson
    I'm a beginner in jQuery area and I have simple question like this : I want to load (AJAX) MySQL result in array, let's say : $row[0] = first name $row[1] = last name $row[2] = phone number I have no problem with PHP part, but I have difficulties to display each of that array content on different id. because syntax I found loads everything processed by PHP : <script type="text/javascript"> $(document).ready(function(){ $('#mysql-result').load('ajax.php'); }); </script> how to get 'First Name', 'Last Name' and 'Phone Number' from PHP with only one time load and still I can put the result in different . thank you.

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  • Hoard allocator not "working"?

    - by Cowboy
    I'm trying to Hoard allocator to work, but it seems it doesn't. I have a benchmark application that does a lot of dynamic memory management. The execution time for Hoard and glibc memory manager is the same. It makes me wonder if I'm doing the right thing. What I do is... export LD_PRELOAD="/path/libhoard.so" g++ main.cpp -O3 -o bm -lpthread -lrt Shouldn't I have to link to Hoard allocator? Does it matter what path (in LD_PRELOAD) is, or can I have whatever path? I'm running Ubuntu 8.04, and g++ 4.2.4 Cheers

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  • g++: how to specify preference of library path?

    - by Heinrich Schmetterling
    I'm compiling a c++ program using g++ and ld. I have a .so library I want to be used during linking. However, a library of the same name exists in /usr/local/lib, and ld is choosing that library over the one I'm directly specifying. How can I fix this? For the examples below, my library file is /my/dir/libfoo.so.0. Things I've tried that don't work: my g++ command is "g++ -g -Wall -o my_binary -L/my/dir -lfoo bar.cpp" adding /my/dir to the beginning or end of my $PATH env variable adding /my/dir/libfoo.so.0 as an argument to g++ Thanks.

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  • How to use a variable inside a _T wrapper?

    - by karikari
    I want to make the hostname part of this string to be variable.. Currently, it is only fix to this URL: _T(" --url=http://www.myurl.com/ --out=c:\\current.png"); I want to make something like this, so the URL is changeable.. _T(" --url=http://www." + myurl + "/ --out=c:\\current.png"); update. Below is my latest attempt: CString one = _T(" --url=http://www."); CString two(url->bstrVal); CString three = _T("/ --out=c:\\current.png"); CString full = one + two + three; ShellExecute(0, _T("open"), // Operation to perform _T("c:\\IECapt"), // Application name _T(full),// Additional parameters 0, // Default directory SW_HIDE); The error is : Error 1 error C2065: 'Lfull' : undeclared identifier c:\test.cpp

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  • Compiling without setting up a project in NetBeans or Visual Studio

    - by aLostMonkey
    Hi, In short: is there a way to compile and run single file in NetBeans or Visual Studio without having to setup and tinker with projects? I'm currently using code::blocks as my IDE. It's fast and very simple: perfect for my needs as a begginner. I wanted to dive a little deeper and try out a more advanced IDE such as NetBeans or Visual Studio. It appears I have to mess with projects and have a setup that seems overkill for having to compile and run one very simple .c/.cpp source file that contains less than 50-100 lines of code etc. Is there a way around this?

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  • Getting 'choice' to work in Highline Ruby Gem without error and getting variable from it

    - by The Warm Jets
    I'm having a couple of problems using Highline in Ruby, and trying to get the choice element, detailed here, to work. At the moment the following code produces the error "error: wrong number of arguments (0 for 1). Use --trace to view backtrace" How do I get the variable out of choice? At the moment I have the 'do' setup, but I have no idea about how to get the variable the user has chosen out and into a variable for use elsewhere. Sorry if this is a bit beginner, I'm brand new to ruby and this is my first project, in at the deep end. Thanks in advance. if agree("Are these files going to be part of a set? ") set_title = ask("Title: ") set_desc = ask("Description:") set_genre = ask("Genre: ") set_label = ask("Record Label: ") set_date = ask_for_date("Release Date (yy-mm-dd): ") set_label = ask("EAN/UPC: ") set_buy = ask("Buy this set link: ") set_tags = ask_for_array("Tags (seperated by space): ") # Sort out license choose do |menu| menu.prompt = "Please choose the license for this set? " menu.choices(:all_rights_reserved, :cc_by) do # put the stuff in a variable end end end # End setup set

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