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  • C++ 'ClassName Not Declared' Error

    - by Arjun Nayini
    I have this cpp file. dsets.cpp: #ifndef DSETS_CPP #define DSET_CPP //Adds elements to the DisjointSet data structure. This function adds //x unconnected roots to the end of the array. void DisjointSets::addelements(int x){ } //Given an int this function finds the root associated with that node. int DisjointSets::find(int x){ return 0; } //This function reorders the uptree in order to represent the union of two //subtrees void DisjointSets::setunion(int x, int y){ } #endif and this header file dsets.h: #ifndef DSETS_H #define DSET_H #include <iostream> #include <vector> using namespace std; class DisjointSets { public: void addelements(int x); int find(int x); void setunion(int x, int y); private: vector<int> x; }; #include "dsets.cpp" #endif And I keep getting an error that is saying that "DisjointSets has no been declared" ~ ~

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  • Visual Studio 2005 - VC++ compiler C1001 on Windows 7

    - by Fritz H
    When I try to build a simple "Hello World" C++ app on Windows 7 Beta, using Visual Studio 2005 (VC++2005) I get a rather generic error C1001 error (Internal compiler error) The compiler seems to just crash, and Windows pops up its (un)helpful This program has stopped working dialog. The file it complains about is mcp1.cpp. Has anyone come across this before? Cheers, Fritz EDIT: The code is: #include <iostream> int main(int argc, char** argv) { std::cout << "Hello!"; return 0; } EDIT 2: I have installed SP1 as well as SP1 for Vista. VS popped up a warning saying it needs SP1 for Vista, but installing it makes no difference. No ideas about what I can possibly do to fix this?

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  • how to send string from/To C++ (6.0) to C++ DLL?

    - by Ahmed Mostafa
    When I send text to my DLL and receive it as char*, something strange happens; if the text is less than 13 characters or greater than 77 characters the text returned is rubbish! Here is my code:- //(1) DLL function: char* __stdcall ApplyArabicMapping( char* input) { // 1-Conver char* to string std::string inputString = input; // 2-Calling our function string encodedStr = Encoding::arabicHandling(inputString); // 3-Convert from String to char* char* returnStr = (char*)encodedStr.c_str(); return (returnStr); } //(2) Calling from C++ console application: char* inputStr = "Some text"; char* resutls = ApplyArabicMapping(inputStr);

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  • Is Boost.Tuple compatible with C++0x variadic templates ?

    - by Thomas Petit
    Hi, I was playing around with variadic templates (gcc 4.5) and hit this problem : template <typename... Args> boost::tuple<Args...> my_make_tuple(Args... args) { return boost::tuple<Args...>(args...); } int main (void) { boost::tuple<int, char> t = my_make_tuple(8, 'c'); } GCC error message : sorry, unimplemented: cannot expand 'Arg ...' into a fixed-length argument list In function 'int my_make_tuple(Arg ...)' If I replace every occurrence of boost::tuple by std::tuple, it compiles fine. Is there a problem in boost tuple implementation ? Or is this a gcc bug ? I must stick with Boost.Tuple for now. Do you know any workaround ? Thanks.

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  • Boost::Archive causing weird linker error.

    - by Dallin Wellington
    Does anyone have a clue why those two lines would cause that linker error? std::ifstream ifs("filename.file"); boost::archive::binary_iarchive iarchv( ifs ); Error 8 fatal error LNK1104: cannot open file 'F:\dev\project\build\win32-unit\tests\Debug\framework_core_tests.lib' ramework_core_tests framework_core_tests The same happens with any Boost::Archive type. Its trying to link against a library of the same name as my executable for some reason when that project doesn't nor never existed and is not defined as a library to link against in my project files.

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  • Selecting an area from displayed image using CImg library

    - by sravan
    hi all, i use CImg for my image processing work. I had written a small piece of code which is follows: #include "../CImg.h" #include <iostream> using namespace std; using namespace cimg_library; int main(int argc,char**argv) { CImg<int> img(argv[1]); CImgDisplay disp; disp.assign(img); while(!disp.is_closed) disp.wait(); return 0; } Now i want to select an area from the displayed image. Can some one tell me how to select an area from displayed image and store the selected pixels, and display the selected region in different display window. If some one can provide code, it will be of great help to me. Thank you all

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  • Implementing 1 to n mapping for ORM c++

    - by karan
    I am writing a project where I need to implement a stripped down version of an ORM solution in C++. I am struck in implementing 1-n relationships for the same. For instance, if the following are the classes: class A { ... } class B { ... std::list<A> _a_list; ... } I have provided load/save methods for loading/saving to the db. Now, if I take the case of B and the following workflow: 1 entry from _a_list is removed 1 entry from _a_list is modified 1 entry is added to _a_list Now, I need to update the db using something like "b.save()". So, what would be the best way to save the changes, i.e, identify the additions, deletions and updates to _a_list.

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  • Reading in 4 bytes at a time

    - by alphomega
    I have a big file full of integers that I'm loading in. I've just started using C++, and I'm trying out the filestream stuff. From everything I've read, it appears I can only read in bytes, So I've had to set up a char array, and then cast it as a int pointer. Is there a way I can read in 4 bytes at a time, and eliminate the need for the char array? const int HRSIZE = 129951336; //The size of the table char bhr[HRSIZE]; //The table int *dwhr; int main() { ifstream fstr; /* load the handranks.dat file */ std::cout << "Loading table.dat...\n"; fstr.open("table.dat"); fstr.read(bhr, HRSIZE); fstr.close(); dwhr = (int *) bhr; }

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  • How to invoke an Objective-C Block via the LLVM C++ API?

    - by smokris
    Say, for example, I have an Objective-C compiled Module that contains something like the following: typedef bool (^BoolBlock)(void); BoolBlock returnABlock(void) { return Block_copy(^bool(void){ printf("Block executing.\n"); return YES; }); } ...then, using the LLVM C++ API, I load that Module and create a CallInst to call the returnABlock() function: Function *returnABlockFunction = returnABlockModule->getFunction(std::string("returnABlock")); CallInst *returnABlockCall = CallInst::Create(returnABlockFunction, "returnABlockCall", entryBlock); How can I then invoke the Block returned via the returnABlockCall object?

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  • Is there a efficient way to do multiple test cases in c?

    - by Ahmed Abdelaal
    I use MS Visual Studio and I am new to C++, so I am just wondering if there is an faster more efficient way to do multiple test cases instead of keep clicking CTRL+F5 and re-opening the console many times. Like for example if I have this code #include <iostream> using namespace std; void main () { int x; cout<<"Enter a number"<<endl; cin>>x; cout<<x*2<<endl; } Is there a way I could try different values of x at once and getting the results together? Thanks

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  • How to log C++ exception if running outside debugger, otherwise rethrow

    - by Stefan Monov
    I wanna do something like this: int main() { try { runApp(); } catch(std::exception const& ex) { if(runningInDebugger()) throw; // let the IDE show me what went wrong else displayMsgBox("Something went wrong! " + ex.what()); } } Needs to work at least in VS2008 but the more debuggers it supports, the better. I want it to check for a debugger at runtime. I don't want to do "#ifdef NDEBUG", because I prefer not to do release builds at all (can't be bothered). So what should I use as a "runningInDebugger()" check?

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  • How, exactly, does the double-stringize trick work?

    - by Peter Hosey
    At least some C preprocessors let you stringize the value of a macro, rather than its name, by passing it through one function-like macro to another that stringizes it: #define STR1(x) #x #define STR2(x) STR1(x) #define THE_ANSWER 42 #define THE_ANSWER_STR STR2(THE_ANSWER) /* "42" */ Example use cases here. This does work, at least in GCC and Clang (both with -std=c99), but I'm not sure how it works in C-standard terms. Is this behavior guaranteed by C99? If so, how does C99 guarantee it? If not, at what point does the behavior go from C-defined to GCC-defined?

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  • how to pass an array into an function and in the function count how many numbers are in a range?

    - by user320950
    #include <iostream> #include <fstream> using namespace std; int calculate_total(int exam1[], int exam2[], int exam3[]); // function that calcualates grades to see how many 90,80,70,60 int exam1[100];// array that can hold 100 numbers for 1st column int exam2[100];// array that can hold 100 numbers for 2nd column int exam3[100];// array that can hold 100 numbers for 3rd column // here i am passing an array into the function calcualate_total int calculate_total(exam1[],exam2[],exam3[]) { int above90=0, above80=0, above70=0, above60=0; if((num<=90) && (num >=100)) { above90++; { if((num<=80) && (num >=89)) { above80++; { if((num<=70) && (num >=79)) { above70++; { if((num<=60) && (num >=69)) { above60++; } } } } } } } }

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  • Determine if a string contains only alphanumeric characters (or a space)

    - by dreamlax
    I'm learning C++ and I am writing a function that determines whether a string contains only alphanumeric characters and spaces. I suppose I am effectively testing whether it matches the regular expression ^[[:alnum:] ]+$ but without using regular expressions. I have seen a lot of algorithms revolve around iterators, so I tried to find a solution that made use of iterators, and this is what I have: #include <algorithm> static inline bool is_not_alnum_space(char c) { return !(isalpha(c) || isdigit(c) || (c == ' ')); } bool string_is_valid(const std::string &str) { return find_if(str.begin(), str.end(), is_not_alnum_space) == str.end(); } Is there a better solution, or a “more C++” way to do this?

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  • system() copy fails, while cmd copy works

    - by Mike
    In cmd.exe, I can execute the command "copy c:\hello.txt c:\hello2.txt" and it worked fine. But in my C program, I ran this piece of code and got the following error: #include <iostream> using namespace std; int main() { system("copy c:\hello.txt c:\hello2.txt"); system("pause"); return 0; } Output: The system cannot find the file specified. Anybody know what is going on here?

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  • Pass temporary object to function that takes pointer

    - by Happy Mittal
    I tried following code : #include<iostream> #include<string> using namespace std; string f1(string s) { return s="f1 called"; } void f2(string *s) { cout<<*s<<endl; } int main() { string str; f2(&f1(str)); } But this code doesn't compile. What I think is : f1 returns by value so it creates temporary, of which I am taking address and passing to f2. Now Please explain me where I am thinking wrong?

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  • C++ Linked List - Reading data from a file with a sentinel

    - by Nick
    So I've done quite a bit of research on this and can't get my output to work correctly. I need to read in data from a file and have it stored into a Linked List. The while loop used should stop once it hits the $$$$$ sentinel. Then I am to display the data (by searching by ID Number[user input]) I am not that far yet I just want to properly display the data and get it read in for right now. My problem is when it displays the data is isn't stopping at the $$$$$ (even if I do "inFile.peek() != EOF and omit the $$$$$) I am still getting an extra garbage record. I know it has something to do with my while loop and how I am creating a new Node but I can't get it to work any other way. Any help would be appreciated. students.txt Nick J Cooley 324123 60 70 80 90 Jay M Hill 412254 70 80 90 100 $$$$$ assign6.h file #pragma once #include <iostream> #include <string> using namespace std; class assign6 { public: assign6(); // constructor void displayStudents(); private: struct Node { string firstName; string midIni; string lastName; int idNum; int sco1; //Test score 1 int sco2; //Test score 2 int sco3; //Test score 3 int sco4; //Test score 4 Node *next; }; Node *head; Node *headPtr; }; assign6Imp.cpp // Implementation File #include "assign6.h" #include <fstream> #include <iostream> #include <string> using namespace std; assign6::assign6() //constructor { ifstream inFile; inFile.open("students.txt"); head = NULL; head = new Node; headPtr = head; while (inFile.peek() != EOF) //reading in from file and storing in linked list { inFile >> head->firstName >> head->midIni >> head->lastName; inFile >> head->idNum; inFile >> head->sco1; inFile >> head->sco2; inFile >> head->sco3; inFile >> head->sco4; if (inFile != "$$$$$") { head->next = NULL; head->next = new Node; head = head->next; } } head->next = NULL; inFile.close(); } void assign6::displayStudents() { int average = 0; for (Node *cur = headPtr; cur != NULL; cur = cur->next) { cout << cur->firstName << " " << cur->midIni << " " << cur->lastName << endl; cout << cur->idNum << endl; average = (cur->sco1 + cur->sco2 + cur->sco3 + cur->sco4)/4; cout << cur->sco1 << " " << cur->sco2 << " " << cur->sco3 << " " << cur->sco4 << " " << "average: " << average << endl; } }

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  • Access violation reading location 0x00184000.

    - by numerical25
    having troubles with the following line HR(md3dDevice->CreateBuffer(&vbd, &vinitData, &mVB)); it appears the CreateBuffer method is having troubles reading &mVB. mVB is defined in box.h and looks like this ID3D10Buffer* mVB; Below is the code it its entirety. this is all files that mVB is in. //Box.cpp #include "Box.h" #include "Vertex.h" #include <vector> Box::Box() : mNumVertices(0), mNumFaces(0), md3dDevice(0), mVB(0), mIB(0) { } Box::~Box() { ReleaseCOM(mVB); ReleaseCOM(mIB); } float Box::getHeight(float x, float z)const { return 0.3f*(z*sinf(0.1f*x) + x*cosf(0.1f*z)); } void Box::init(ID3D10Device* device, float m, float n, float dx) { md3dDevice = device; mNumVertices = m*n; mNumFaces = 12; float halfWidth = (n-1)*dx*0.5f; float halfDepth = (m-1)*dx*0.5f; std::vector<Vertex> vertices(mNumVertices); for(DWORD i = 0; i < m; ++i) { float z = halfDepth - (i * dx); for(DWORD j = 0; j < n; ++j) { float x = -halfWidth + (j* dx); float y = getHeight(x,z); vertices[i*n+j].pos = D3DXVECTOR3(x, y, z); if(y < -10.0f) vertices[i*n+j].color = BEACH_SAND; else if( y < 5.0f) vertices[i*n+j].color = LIGHT_YELLOW_GREEN; else if (y < 12.0f) vertices[i*n+j].color = DARK_YELLOW_GREEN; else if (y < 20.0f) vertices[i*n+j].color = DARKBROWN; else vertices[i*n+j].color = WHITE; } } D3D10_BUFFER_DESC vbd; vbd.Usage = D3D10_USAGE_IMMUTABLE; vbd.ByteWidth = sizeof(Vertex) * mNumVertices; vbd.BindFlags = D3D10_BIND_VERTEX_BUFFER; vbd.CPUAccessFlags = 0; vbd.MiscFlags = 0; D3D10_SUBRESOURCE_DATA vinitData; vinitData.pSysMem = &vertices; HR(md3dDevice->CreateBuffer(&vbd, &vinitData, &mVB)); //create the index buffer std::vector<DWORD> indices(mNumFaces*3); // 3 indices per face int k = 0; for(DWORD i = 0; i < m-1; ++i) { for(DWORD j = 0; j < n-1; ++j) { indices[k] = i*n+j; indices[k+1] = i*n+j+1; indices[k+2] = (i*1)*n+j; indices[k+3] = (i*1)*n+j; indices[k+4] = i*n+j+1; indices[k+5] = (i*1)*n+j+1; k+= 6; } } D3D10_BUFFER_DESC ibd; ibd.Usage = D3D10_USAGE_IMMUTABLE; ibd.ByteWidth = sizeof(DWORD) * mNumFaces*3; ibd.BindFlags = D3D10_BIND_INDEX_BUFFER; ibd.CPUAccessFlags = 0; ibd.MiscFlags = 0; D3D10_SUBRESOURCE_DATA iinitData; iinitData.pSysMem = &indices; HR(md3dDevice->CreateBuffer(&ibd, &iinitData, &mIB)); } void Box::Draw() { UINT stride = sizeof(Vertex); UINT offset = 0; md3dDevice->IASetVertexBuffers(0, 1, &mVB, &stride, &offset); md3dDevice->IASetIndexBuffer(mIB, DXGI_FORMAT_R32_UINT, 0); md3dDevice->DrawIndexed(mNumFaces*3, 0 , 0); } //Box.h #ifndef _BOX_H #define _BOX_H #include "d3dUtil.h" Box.h class Box { public: Box(); ~Box(); void init(ID3D10Device* device, float m, float n, float dx); void Draw(); float getHeight(float x, float z)const; private: DWORD mNumVertices; DWORD mNumFaces; ID3D10Device* md3dDevice; ID3D10Buffer* mVB; ID3D10Buffer* mIB; }; #endif Thanks again for the help

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  • correct way to store an exception in a variable

    - by Evan Teran
    I have an API which internally has some exceptions for error reporting. The basic structure is that it has a root exception object which inherits from std::exception, then it will throw some subclass of that. Since catching an exception thrown in one library and catching it in another can lead to undefined behavior (at least Qt complains about it and disallows it in many contexts). I would like to wrap the library calls in functions which will return a status code, and if an exception occurred, a copy of the exception object. What is the best way to store an exception (with it's polymorphic behavior) for later use? I believe that the c++0x futures API makes use of something like this. So what is the best approach? The best I can think of is to have a clone() method in each exception class which will return a pointer to an exception of the same type. But that's not very generic and doesn't deal with standard exceptions at all. Any thoughts?

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  • "Ambiguous template specialization" problem

    - by Setien
    I'm currently porting a heap of code that has previously only been compiled with Visual Studio 2008. In this code, there's an arrangement like this: template <typename T> T convert( const char * s ) { // slow catch-all std::istringstream is( s ); T ret; is >> ret; return ret; } template <> inline int convert<int>( const char * s ) { return (int)atoi( s ); } Generally, there are a lot of specializations of the templated function with different return types that are invoked like this: int i = convert<int>( szInt ); The problem is, that these template specializations result in "Ambiguous template specialization". If it was something besides the return type that differentiated these function specializations, I could obviously just use overloads, but that's not an option. How do I solve this without having to change all the places the convert functions are called?

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  • Why do I get a "warning: no newline at end of file" ?

    - by user198729
    The file is a helloworld.cpp: #include <iostream> using namespace std; int main() { if(true) cout << "!!!Hello World!!!" << endl; // prints !!!Hello World!!! return 0; } But when I build it,get a warning: g++ -Wall -O2 -c -o hw.o hw.cpp hw.cpp:8:2: warning: no newline at end of file g++ -o myprog hw.o If I add a newline at the end,the warning will go. Why is that newline at end of file recommended in a cpp source file?

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  • dose not name a type error in c++

    - by user985316
    #include <math.h> #include <stdlib.h> #include <stdio.h> #include <vector> #define IE 40 #define JE 40 #define KE 40 #define ia 7 #define ja 7 #define ka 7 #define NFREQS 3 using namespace std; main() float l,m,n,i,j,k,ic,jc,kc,nsteps,n_pml; float ddx,dt,T,epsz,muz,pi,eaf,npml; int ib,jb,kb; . . . . ic=IE*0.5 ; jc=JE*0.5 ; ....'ic'dose not name a type. ....'jc'dose not name a type.

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  • How to parse a tar file in C++

    - by Brendan Long
    What I want to do is download a .tar file with multiple directories with 2 files each. The problem is I can't find a way to read the tar file without actually extracting the files (using tar). The perfect solution would be something like: #include <easytar> Tarfile tar("somefile.tar"); std::string currentFile, currentFileName; for(int i=0; i<tar.size(); i++){ file = tar.getFileText(i); currentFileName = tar.getFileName(i); // do stuff with it } I'm probably going to have to write this myself, but any ideas would be appreciated..

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