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  • C++ Templates: Convincing self against code bloat

    - by ArunSaha
    I have heard about code bloats in context of C++ templates. I know that is not the case with modern C++ compilers. But, I want to construct an example and convince myself. Lets say we have a class template< typename T, size_t N > class Array { public: T * data(); private: T elems_[ N }; }; template< typename T, size_t N > T * Array<T>::data() { return elems_; } Further, let's say types.h contains typedef Array< int, 100 > MyArray; x.cpp contains MyArray ArrayX; and y.cpp contains MyArray ArrayY; Now, how can I verify that the code space for MyArray::data() is same for both ArrayX and ArrayY? What else I should know and verify from this (or other similar simple) examples? If there is any g++ specific tips, I am interested for that too. PS: Regarding bloat, I am concerned even for the slightest of bloats, since I come from embedded context.

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  • Friends, templates, overloading <<

    - by Crystal
    I'm trying to use friend functions to overload << and templates to get familiar with templates. I do not know what these compile errors are: Point.cpp:11: error: shadows template parm 'class T' Point.cpp:12: error: declaration of 'const Point<T>& T' for this file #include "Point.h" template <class T> Point<T>::Point() : xCoordinate(0), yCoordinate(0) {} template <class T> Point<T>::Point(T xCoordinate, T yCoordinate) : xCoordinate(xCoordinate), yCoordinate(yCoordinate) {} template <class T> std::ostream &operator<<(std::ostream &out, const Point<T> &T) { std::cout << "(" << T.xCoordinate << ", " << T.yCoordinate << ")"; return out; } My header looks like: #ifndef POINT_H #define POINT_H #include <iostream> template <class T> class Point { public: Point(); Point(T xCoordinate, T yCoordinate); friend std::ostream &operator<<(std::ostream &out, const Point<T> &T); private: T xCoordinate; T yCoordinate; }; #endif My header also gives the warning: Point.h:12: warning: friend declaration 'std::ostream& operator<<(std::ostream&, const Point<T>&)' declares a non-template function Which I was also unsure why. Any thoughts? Thanks.

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  • I can't get that `bus error` to stop sucking.

    - by Koning Baard XIV
    I have this a class called PPString: PPString.h #ifndef __CPP_PPString #define __CPP_PPString #include "PPObject.h" class PPString : public PPObject { char *stringValue[]; public: char *pointerToCharString(); void setCharString(char *charString[]); void setCharString(const char charString[]); }; #endif PPString.cpp #include "PPString.h" char *PPString::pointerToCharString() { return *stringValue; } void PPString::setCharString(char *charString[]) { *stringValue = *charString; } void PPString::setCharString(const char charString[]) { *stringValue = (char *)charString; } I'm trying to set the stringValue using std::cin: main.cpp PPString myString; myString.setCharString("LOLZ"); std::cout << myString.pointerToCharString() << std::endl; char *aa[1000]; std::cin >> *aa; myString.setCharString(aa); std::cout << myString.pointerToCharString() << std::endl; The first one, which uses a const char works, but the second one, with a char doesn't, and I get this output: copy and paste from STDOUT LOLZ im entering a string now... Bus error where the second line is what I entered, followed by pressing the return key. Can anyone help me fixing this? Thanks...

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  • Strange Access Denied warning when running the simplest C++ program.

    - by DaveJohnston
    I am just starting to learn C++ (coming from a Java background) and I have come across something that I can't explain. I am working through the C++ Primer book and doing the exercises. Every time I get to a new exercise I create a new .cpp file and set it up with the main method (and any includes I think I will need) e.g.: #include <list> #include <vector> int main(int argc, char **args) { } and just to make sure I go to the command prompt and compile and run: g++ whatever.cpp a.exe Normally this works just fine and I start working on the exercise, but I just did it and got a strange error. It compiles fine, but when I run it it says Access Denied and AVG pops up telling me that a threat has been detected 'Trojan Horse Generic 17.CKZT'. I tried compiling again using the Microsoft Compiler (cl.exe) and it runs fines. So I went back, and added: #include <iostream> compiled using g++ and ran. This time it worked fine. So can anyone tell me why AVG would report an empty main method as a trojan horse but if the iostream header is included it doesn't?

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  • Sharing a global/static variable between a process and DLL

    - by minjang
    I'd like to share a static/global variable only between a process and a dll that is invoked by the process. The exe and dll are in the same memory address space. I don't want the variable to be shared among other processes. Elaboration of the problem: Say that there is a static/global variable x in a.cpp. Both the exe foo.exe and the dll bar.dll have a.cpp, so the variable x is in both images. Now, foo.exe dynamically loads (or statically) bar.dll. Then, the problem is whether the variable x is shared by the exe and dll, or not. In Windows, these two guys never share the x: the exe and dll will have a separate copy of x. However, in Linux, the exe and dll do share the variable x. Unfortunately, I want the behavior of Linux. I first considered using pragma data_seg on Windows. However, even if I correctly setup the shared data segment, foo.exe and bar.dll never shares the x. Recall that bar.dll is loaded into the address space of foo.exe. However, if I run another instance of foo.exe, then x is shared. But, I don't want x to be shared by different processes. So, using data_seg was failed. I may it use a memory-mapped file by making an unique name between exe and dll, which I'm trying now. Two questions: Why the behavior of Linux and Windows is different? Can anyone explain more about this? What would be most easiest way to solve this problem on Windows?

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  • C++ arrays as parameters, EDIT: now includes variable scoping

    - by awshepard
    Alright, I'm guessing this is an easy question, so I'll take the knocks, but I'm not finding what I need on google or SO. I'd like to create an array in one place, and populate it inside a different function. I define a function: void someFunction(double results[]) { for (int i = 0; i<100; ++i) { for (int n = 0; n<16; ++n) //note this iteration limit { results[n] += i * n; } } } That's an approximation to what my code is doing, but regardless, shouldn't be running into any overflow or out of bounds issues or anything. I generate an array: double result[16]; for(int i = 0; i<16; i++) { result[i] = -1; } then I want to pass it to someFunction someFunction(result); When I set breakpoints and step through the code, upon entering someFunction, results is set to the same address as result, and the value there is -1.000000 as expected. However, when I start iterating through the loop, results[n] doesn't seem to resolve to *(results+n) or *(results+n*sizeof(double)), it just seems to resolve to *(results). What I end up with is that instead of populating my result array, I just get one value. What am I doing wrong? EDIT Oh fun, I have a typo: it wasn't void someFunction(double results[]). It was: void someFunction(double result[])... So perhaps this is turning into a scoping question. If my double result[16] array is defined in a main.cpp, and someFunction is defined in a Utils.h file that's included by the main.cpp, does the result variable in someFunction then wreak havoc on the result array in main?

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  • How to iterate properly across a const set?

    - by Jared
    I'm working on a program that's supposed to represent a graph. My issue is in my printAdjacencyList function. Basically, I have a Graph ADT that has a member variable "nodes", which is a map of the nodes of that graph. Each Node has a set of Edge* to the edges it is connected to. I'm trying to iterate across each node in the graph and each edge of a node. void MyGraph::printAdjacencyList() { std::map<std::string, MyNode*>::iterator mit; std::set<MyEdge*>::iterator sit; for (mit = nodes.begin(); mit != nodes.end(); mit++ ) { std::cout << mit->first << ": {"; const std::set<MyEdge*> edges = mit->second->getEdges(); for (sit = edges.begin(); sit != edges.end(); sit++) { std::pair<MyNode*, MyNode*> edgeNodes = *sit->getEndpoints(); } } std::cout << " }" << std::endl; } getEdges is declared as: const std::set<MyEdge*>& getEdges() { return edges; }; and get Endpoints is declared as: const std::pair<MyNode*, MyNode*>& getEndpoints() { return nodes; }; The compiler error I'm getting is: MyGraph.cpp:63: error: request for member `getEndpoints' in `*(&sit)->std::_Rb_tree_const_iterator<_Tp>::operator-> [with _Tp = MyEdge*]()', which is of non-class type `MyEdge* const' MyGraph.cpp:63: warning: unused variable 'edgeNodes' I have figured out that this probably means I'm misusing const somewhere, but I can't figure out where for the life of me. Any information would be appreciated. Thanks!

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  • static initialization confusion

    - by Happy Mittal
    I am getting very confused in some concepts in c++. For ex: I have following two files //file1.cpp class test { static int s; public: test(){s++;} }; static test t; int test::s=5; //file2.cpp #include<iostream> using namespace std; class test { static int s; public: test(){s++;} static int get() { return s; } }; static test t; int main() { cout<<test::get()<<endl; } Now My question is : 1. How two files link successfully even if they have different class definitions? 2. Are the static member s of two classes related because I get output as 7. Please explain this concept of statics.

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  • refactoring my code. My headers (Header Guard Issues)

    - by numerical25
    I had a post similar to this awhile ago based on a error I was getting. I was able to fix it but since then I been having trouble doing things because headers keep blocking other headers from using code. Honestly, these headers are confusing me and if anyone has any resources that will address these types of issues, that will be helpful. What I essentially want to do is be able to have rModel.h be included inside RenderEngine.h. every time I add rModel.h to RenderEngine.h, rModel.h is no longer able to use RenderEngine.h. (rModel.h has a #include of RenderEngine.h as well). So in a nutshell, RenderEngine and rModel need to use each others functionalities. On top of all this confusion, the Main.cpp needs to use RenderEngine. stdafx.h #include "targetver.h" #define WIN32_LEAN_AND_MEAN // Exclude rarely-used stuff from Windows headers // Windows Header Files: #include <windows.h> // C RunTime Header Files #include <stdlib.h> #include <malloc.h> #include <memory.h> #include <tchar.h> #include "resource.h" main.cpp #include "stdafx.h" #include "RenderEngine.h" #include "rModel.h" // Global Variables: RenderEngine go; rModel *g_pModel; ...code........... rModel.h #ifndef _MODEL_H #define _MODEL_H #include "stdafx.h" #include <vector> #include <string> #include "rTri.h" #include "RenderEngine.h" ........Code RenderEngine.h #pragma once #include "stdafx.h" #include "d3d10.h" #include "d3dx10.h" #include "dinput.h" #include "rModel.h" .......Code......

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  • [c++] accessing the hidden 'this' pointer

    - by Kyle
    I have a GUI architecture wherein elements fire events like so: guiManager->fireEvent(BUTTON_CLICKED, this); Every single event fired passes 'this' as the caller of the event. There is never a time I dont want to pass 'this', and further, no pointer except for 'this' should ever be passed. This brings me to a problem: How can I assert that fireEvent is never given a pointer other than 'this', and how can I simplify (and homogenize) calls to fireEvent to just: guiManager->fireEvent(BUTTON_CLICKED); At this point, I'm reminded of a fairly common compiler error when you write something like this: class A { public: void foo() {} }; class B { void oops() { const A* a = new A; a->foo(); } }; int main() { return 0; } Compiling this will give you ../src/sandbox.cpp: In member function ‘void B::oops()’: ../src/sandbox.cpp:7: error: passing ‘const A’ as ‘this’ argument of ‘void A::foo()’ discards qualifiers because member functions pass 'this' as a hidden parameter. "Aha!" I say. This (no pun intended) is exactly what I want. If I could somehow access the hidden 'this' pointer, it would solve both issues I mentioned earlier. The problem is, as far as I know you can't (can you?) and if you could, there would be outcries of "but it would break encapsulation!" Except I'm already passing 'this' every time, so what more could it break. So, is there a way to access the hidden 'this', and if not are there any idioms or alternative approaches that are more elegant than passing 'this' every time?

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  • Failed to specialize function template

    - by citizencane
    This is homework, although it's already submitted with a different approach. I'm getting the following from Visual Studio 2008 error C2893: Failed to specialize function template 'void std::sort(_RanIt,_RanIt,_Pr)' The code is as follows main.cpp Database<> db; db.loadDatabase(); db.sortDatabase(sort_by_title()); Database.cpp void Database<C>::sortDatabase(const sort_by &s) { std::sort(db_.begin(), db_.end(), s); } And the function objects are defined as struct sort_by : public std::binary_function<const Media *, const Media *, bool> { virtual bool operator()(const Media *l, const Media *r) const = 0; }; struct sort_by_title : public sort_by { bool operator()(const Media *l, const Media *r) const { ... } }; ... What's the cure here? [Edit] Sorry, maybe I should have made the inheritance clear template <typename C = std::vector<Media *> > class Database : public IDatabase<C> [/Edit]

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  • Why it's can be compiled in GNU/C++, can't compiled in VC++2010 RTM?

    - by volnet
    #include #include #include #include "copy_of_auto_ptr.h" #ifdef _MSC_VER #pragma message("#include ") #include // http://gcc.gnu.org/onlinedocs/gcc/Diagnostic-Pragmas.html#Diagnostic-Pragmas #endif /* case 1-4 is the requirement of the auto_ptr. which form http://ptgmedia.pearsoncmg.com/images/020163371X/autoptrupdate/auto_ptr_update.html */ /* case 1. (1) Direct-initialization, same type, e.g. */ std::auto_ptr source_int() { // return std::auto_ptr(new int(3)); std::auto_ptr tmp(new int(3)); return tmp; } /* case 2. (2) Copy-initialization, same type, e.g. */ void sink_int(std::auto_ptr p) { std::cout source_derived() { // return std::auto_ptr(new Derived()); std::auto_ptr tmp(new Derived()); return tmp; } /* case 4. (4) Copy-initialization, base-from-derived, e.g. */ void sink_base( std::auto_ptr p) { p-go(); } int main(void) { /* // auto_ptr */ // case 1. // auto_ptr std::auto_ptr p_int(source_int()); std::cout p_derived(source_derived()); p_derived-go(); // case 4. // auto_ptr sink_base(source_derived()); return 0; } In Eclipse(GNU C++.exe -v gcc version 3.4.5 (mingw-vista special r3)) it's two compile error: Description Resource Path Location Type initializing argument 1 of void sink_base(std::auto_ptr<Base>)' from result ofstd::auto_ptr<_Tp::operator std::auto_ptr<_Tp1() [with _Tp1 = Base, _Tp = Derived]' auto_ptr_ref_research.cpp auto_ptr_ref_research/auto_ptr_ref_research 190 C/C++ Problem Description Resource Path Location Type no matching function for call to `std::auto_ptr::auto_ptr(std::auto_ptr)' auto_ptr_ref_research.cpp auto_ptr_ref_research/auto_ptr_ref_research 190 C/C++ Problem But it's right in VS2010 RTM. Questions: Which compiler stand for the ISO C++ standard? The content of case 4 is the problem "auto_ptr & auto_ptr_ref want to resolve?"

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  • C++ Vector of vectors is messing with me

    - by xbonez
    If I put this code in a .cpp file and run it, it runs just fine: #include <iostream> #include <vector> #include <string> using namespace std; typedef vector<int> row; typedef vector<row> myMatrix; void main() { //cout << endl << "test" << endl; myMatrix mat(2,2); mat[0][1] = 2; cout << endl << mat[0][1] << endl; } But, if I make a .h and a .cpp file with the .h file like this, it gives me boatloads of errors. #ifndef _grid_ #define _grid_ #include<iostream> #include<vector> #include<string> using namespace std; typedef vector<int> row; typedef vector<row> myMatrix; class grid { public: grid(); ~grid(); int getElement(unsigned int ri, unsigned int ci); bool setElement(unsigned int ri, unsigned int ci, unsigned int value); private: myMatrix sudoku_(9,9); }; #endif These are some of the errors I get: warning C4091: 'typedef ' : ignored on left of 'int' when no variable is declared error C4430: missing type specifier - int assumed. Note: C++ does not support default-int

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  • I cant put a string in a switch nor an array in a class

    - by TimothyTech
    Okay, im making a pretty big file in my opinion, so i wanted to separate it into several files for cleaner code. so i have my main .cpp file and two header files holding my classes. well the header files dont hold strings, it aboslutely wont budge. i call the library in both my .cpp file and even tried it in my header file. another issue i ran into is using strings to make switches function, reason being if i use integers in a switch if the user inputs a alphabetical character the program goes into an endless loop. string choice; switch (choice) { case "1" : //... break; case "2" : //... break; } and my last issue is when i create an object in a case it gives an error. says cross initialization of object. string choice; switch (choice) { case "1" : Class object; break; case "2" : //... break; }

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  • how to solve a weired swig python c++ interfacing type error

    - by user2981648
    I want to use swig to switch a simple cpp function to python and use "scipy.integrate.quadrature" function to calculate the integration. But python 2.7 reports a type error. Do you guys know what is going on here? Thanks a lot. Furthermore, "scipy.integrate.quad" runs smoothly. So is there something special for "scipy.integrate.quadrature" function? The code is in the following: File "testfunctions.h": #ifndef TESTFUNCTIONS_H #define TESTFUNCTIONS_H double test_square(double x); #endif File "testfunctions.cpp": #include "testfunctions.h" double test_square(double x) { return x * x; } File "swig_test.i" : /* File : swig_test.i */ %module swig_test %{ #include "testfunctions.h" %} /* Let's just grab the original header file here */ %include "testfunctions.h" File "test.py": import scipy.integrate import _swig_test print scipy.integrate.quadrature(_swig_test.test_square, 0., 1.) error info: UMD has deleted: _swig_test Traceback (most recent call last): File "<stdin>", line 1, in <module> File "C:\Python27\lib\site-packages\spyderlib\widgets\externalshell\sitecustomize.py", line 523, in runfile execfile(filename, namespace) File "D:\data\haitaliu\Desktop\Projects\swig_test\Release\test.py", line 4, in <module> print scipy.integrate.quadrature(_swig_test.test_square, 0., 1.) File "C:\Python27\lib\site-packages\scipy\integrate\quadrature.py", line 161, in quadrature newval = fixed_quad(vfunc, a, b, (), n)[0] File "C:\Python27\lib\site-packages\scipy\integrate\quadrature.py", line 61, in fixed_quad return (b-a)/2.0*sum(w*func(y,*args),0), None File "C:\Python27\lib\site-packages\scipy\integrate\quadrature.py", line 90, in vfunc return func(x, *args) TypeError: in method 'test_square', argument 1 of type 'double'

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  • __declspec(dllimport) causes compiler crash on MSVC 2010

    - by Zero
    In a *.cpp file, trying to use a third party lib: #define DLL_IMPORT #include <thirdParty.h> // Third party header has code like: // #ifdef DLL_IMPORT // #define DLL_DECL __declspec(dllimport) // fatal error C1001: An internal error has occurred in the compiler. Alternative: #define NO_DLL #include <thirdParty.h> // Third party header has code like: // #elif defined(NO_DLL) // #define DLL_DECL // Compiles fine, but linker errors as can't find DLL functions // I can reproduce results by remove macros and #define all together and manually editing the third party files to have __declspec(dllimport) or not Has anyone come across anything similar, or can hint at the cause? (which is created using CMake). Above is actual example of 2 line *.cpp that crashes so it's narrowed down to something in the #include. The following also work fine: Compile the examples provided by the third party (they provide a *.sln) that use dllimport/export so it doesn't appear to be the fault of the library Compile the third party lib as part of the production project (so dllexport works fine) I've trawled the project settings pages of the two projects to try and spot differences, but have come up blank. Of course, it's possible I'm missing something as those settings pages are not the easiest to navigate. I'll get access to VS2008 in a day or so, so can compare with that. The third party library is MySql++.

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  • Why is function's length information of other shared lib in ELF?

    - by minastaros
    Our project (C++, Linux, gcc, PowerPC) consists of several shared libraries. When releasing a new version of the package, only those libs should change whose source code was actually affected. With "change" I mean absolute binary identity (the checksum over the file is compared. Different checksum - different version according to the policy). (I should mention that the whole project is always built at once, no matter if any code has changed or not per library). Usually this can by achieved by hiding private parts of the included Header files and not changing the public ones. However, there was a case where just a delete was added to the destructor of a class TableManager (in the TableManager.cpp file!) of library libTableManager.so, and yet the binary/checksum of library libB.so (which uses class TableManager ) has changed. TableManager.h: class TableManager { public: TableManager(); ~TableManager(); private: int* myPtr; } TableManager.cpp: TableManager::~TableManager() { doSomeCleanup(); delete myPtr; // this delete has been added } By inspecting libB.so with readelf --all libB.so, looking at the .dynsym section, it turned out that the length of all functions, even the dynamically used ones from other libraries, are stored in libB! It looks like this (length is the 668 in the 3rd column): 527: 00000000 668 FUNC GLOBAL DEFAULT UND _ZN12TableManagerD1Ev So my questions are: Why is the length of a function actually stored in the client lib? Wouldn't a start address be sufficient? Can this be suppressed somehow when compiling/linking of libB.so (kind of "stripping")? We would really like to reduce this degree of dependency...

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  • an error "has no member named"

    - by helloWorld
    I have this snippet of the code account.cpp #include "account.h" #include <iostream> #include <string> using namespace std; Account::Account(string firstName, string lastName, int id) : strFirstName(firstName), strLastName(lastName), nID(id) {} void Account::printAccount(){ cout << strFirstName; } account.h #include <string> using std::string; class Account{ private: string strLastName; //Client's last name string strFirstName; //Client's first name int nID; //Client's ID number int nLines; //Number of lines related to account double lastBill; public: Account(string firstName, string lastName, int id); void printAccount(); }; company.h #ifndef CELLULAR_COMPANY_H #define CELLULAR_COMPANY_H #include <string> #include <list> #include <iostream> #include "account.h" using namespace std; class Company { private: list<Account> listOfAccounts; public: void addAccount(string firstName, string lastName, int id) { Account newAccount(firstName, lastName, id); listOfAccounts.push_back(newAccount); } void printAccounts(){ for(list<Account>::iterator i = listOfAccounts.begin(); i != listOfAccounts.end(); ++i){ i.printAccount; //here bug } } }; #endif // CELLULAR_COMPANY_H main.cpp #include "cellularcompany.h" int main(){ Company newCompany; newCompany.addAccount("Pavel", "Nedved", 11111); newCompany.printAccounts(); return 0; } can somebody please explain what does my error mean? thanks in advance (I have it in company.h see comment there) I have bug 'struct std::_List_iterator<Account>' has no member named 'printAccount'

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  • Setting pixel values in Nvidia NPP ImageCPU objects?

    - by solvingPuzzles
    In the Nvidia Performance Primitives (NPP) image processing examples in the CUDA SDK distribution, images are typically stored on the CPU as ImageCPU objects, and images are stored on the GPU as ImageNPP objects. boxFilterNPP.cpp is an example from the CUDA SDK that uses these ImageCPU and ImageNPP objects. When using a filter (convolution) function like nppiFilter, it makes sense to define a filter as an ImageCPU object. However, I see no clear way setting the values of an ImageCPU object. npp::ImageCPU_32f_C1 hostKernel(3,3); //allocate space for 3x3 convolution kernel //want to set hostKernel to [-1 0 1; -1 0 1; -1 0 1] hostKernel[0][0] = -1; //this doesn't compile hostKernel(0,0) = -1; //this doesn't compile hostKernel.at(0,0) = -1; //this doesn't compile How can I manually put values into an ImageCPU object? Notes: I didn't actually use nppiFilter in the code snippet; I'm just mentioning nppiFilter as a motivating example for writing values into an ImageCPU object. The boxFilterNPP.cpp example doesn't involve writing directly to an ImageCPU object, because nppiFilterBox is a special case of nppiFilter that uses a built-in gaussian smoothing filter (probably something like [1 1 1; 1 1 1; 1 1 1]).

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  • boost::function & boost::lambda - call site invocation & accessing _1 and _2 as the type

    - by John Dibling
    Sorry for the confusing title. Let me explain via code: #include <string> #include <boost\function.hpp> #include <boost\lambda\lambda.hpp> #include <iostream> int main() { using namespace boost::lambda; boost::function<std::string(std::string, std::string)> f = _1.append(_2); std::string s = f("Hello", "There"); std::cout << s; return 0; } I'm trying to use function to create a function that uses the labda expressions to create a new return value, and invoke that function at the call site, s = f("Hello", "There"); When I compile this, I get: 1>------ Build started: Project: hacks, Configuration: Debug x64 ------ 1>Compiling... 1>main.cpp 1>.\main.cpp(11) : error C2039: 'append' : is not a member of 'boost::lambda::lambda_functor<T>' 1> with 1> [ 1> T=boost::lambda::placeholder<1> 1> ] Using MSVC 9. My fundamental understanding of function and lambdas may be lacking. The tutorials and docs did not help so far this morning. How do I do what I'm trying to do?

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  • learning C++ from java, trying to make a linked list.

    - by kyeana
    I just started learning c++ (coming from java) and am having some serious problems with doing anything :P Currently, i am attempting to make a linked list, but must be doing something stupid cause i keep getting "void value not ignored as it ought to be" compile errors (i have it marked where it is throwing it bellow). If anyone could help me with what im doing wrong, i would be very grateful :) Also, I am not used to having the choice of passing by reference, address, or value, and memory management in general (currently i have all my nodes and the data declared on the heap). If anyone has any general advice for me, i also wouldn't complain :P Key code from LinkedListNode.cpp LinkedListNode::LinkedListNode() { //set next and prev to null pData=0; //data needs to be a pointer so we can set it to null for //for the tail and head. pNext=0; pPrev=0; } /* * Sets the 'next' pointer to the memory address of the inputed reference. */ void LinkedListNode::SetNext(LinkedListNode& _next) { pNext=&_next; } /* * Sets the 'prev' pointer to the memory address of the inputed reference. */ void LinkedListNode::SetPrev(LinkedListNode& _prev) { pPrev=&_prev; } //rest of class Key code from LinkedList.cpp #include "LinkedList.h" LinkedList::LinkedList() { // Set head and tail of linked list. pHead = new LinkedListNode(); pTail = new LinkedListNode(); /* * THIS IS WHERE THE ERRORS ARE. */ *pHead->SetNext(*pTail); *pTail->SetPrev(*pHead); } //rest of class

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  • Extracting specific words that end with .c and .h [on hold]

    - by Alberto Mederos
    I have a very big list of file names that end with a the following: .c .h .cpp and much more. I need to extract file names that end with .c and .h How do I do that? Also, how could I add quotation marks to the beginning and end of the word, followed with a comma? For example, if I have this in the list: mi_var.c How could I extract it from a very big list, and everything else that ends in .c and replace it to have quotation marks and a comma at the end? Like this: "mi_var.c", I'm new to this, any help is greatly appreciated. Here is part of the list: gsd5t_image.c, gsd5t_image_sqif.c, proc_arm.c, proc_cortex.c, proc_k32.c, proc_k32_entry.s, proc_k32_test.c, proc_k32_test_start.s, rom_sub_functions.s, rom_sub_functions_gcc.s, sqif_jump_table.s, sqif_jump_table_gcc.s, tracker_wrapper_functions.s, vector_M0.c, ptimer.c, ptimer_arm.c, ptimer_internal.h, ptimer_internal_arm.h, ptimer_internal_k32.h, ptimer_k32.c, RstMod_if.h, drvRstMod.h, tbus.dxy, tbus_common.c, tbus_common.h, act.c, act.h, act.msgs, act_if.c, act_if.h, sat_signal_processor.c, sat_signal_processor.h, ssp.dxy, ssp.msgs, ssp_acq_handlers.c, ssp_acq_handlers.h, ssp_atx_if.c, ssp_atx_if.h, ssp_bitsync_handlers.c, ssp_bitsync_handlers.h, ssp_cohver_handlers.c, ssp_cohver_handlers.h, ssp_cwscan_handlers.c, ssp_cwscan_handlers.h, ssp_track_handlers.c, ssp_track_handlers.h, ssp_atx_if_test_sort.c, ssp_hack.c, ssp_hack.h, ssp_suite.cpp, ssp_suite.h, ssptloop.c, ssptloop.h, sss.dxy, sss.msgs, sss_atx_if.c, sss_atx_if.h, strong_signal_scan.c, So how to extract certain names?

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  • 'area' not declared in this scope

    - by user1641173
    I've just started learning c++ and am trying to write a program for finding the area of a circle. I've written the program and whenever I try to compile it I get 2 error messages. The first is: areaofcircle.cpp:9:14: error: expected unqualified-id before numeric constant and the second is: areaofcircle.cpp:18:5: error: 'area' was not declared in this scope What should I do? I would post a picture, but I'm a new user, so I can't. #include <iostream> using namespace std; #define pi 3.1415926535897932384626433832795 int main() { // Create three float variable values: r, pi, area float r, pi, area; cout << "This program computes the area of a circle." << endl; // Prompt user to enter the radius of the circle, read input value into variable r cout << "Enter the radius of the circle " << endl; cin >> r; // Square r and then multiply by pi area = r * r * pi; cout << "The area is " << area << "." << endl; }

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