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  • Why isn't this file reading/writing program working?

    - by user320950
    This program is supposed to read files and write them. I took the file open checks out because they kept causing errors. The problem is that the files open like they are supposed to and the names are correct but nothing is on any of the text screens. Do you know what is wrong? #include<iostream> #include<fstream> #include<cstdlib> #include<iomanip> using namespace std; int main() { ifstream in_stream; // reads itemlist.txt ofstream out_stream1; // writes in items.txt ifstream in_stream2; // reads pricelist.txt ofstream out_stream3;// writes in plist.txt ifstream in_stream4;// read recipt.txt ofstream out_stream5;// write display.txt float price=' ',curr_total=0.0; int wrong=0; int itemnum=' '; char next; in_stream.open("ITEMLIST.txt", ios::in); // list of avaliable items out_stream1.open("listWititems.txt", ios::out); // list of avaliable items in_stream2.open("PRICELIST.txt", ios::in); out_stream3.open("listWitdollars.txt", ios::out); in_stream4.open("display.txt", ios::in); out_stream5.open("showitems.txt", ios::out); in_stream.close(); // closing files. out_stream1.close(); in_stream2.close(); out_stream3.close(); in_stream4.close(); out_stream5.close(); system("pause"); in_stream.setf(ios::fixed); while(in_stream.eof()) { in_stream >> itemnum; cin.clear(); cin >> next; } out_stream1.setf(ios::fixed); while (out_stream1.eof()) { out_stream1 << itemnum; cin.clear(); cin >> next; } in_stream2.setf(ios::fixed); in_stream2.setf(ios::showpoint); in_stream2.precision(2); while((price== (price*1.00)) && (itemnum == (itemnum*1))) { while (in_stream2 >> itemnum >> price) // gets itemnum and price { while (in_stream2.eof()) // reads file to end of file { in_stream2 >> itemnum; in_stream2 >> price; price++; curr_total= price++; in_stream2 >> curr_total; cin.clear(); // allows more reading cin >> next; } } } out_stream3.setf(ios::fixed); out_stream3.setf(ios::showpoint); out_stream3.precision(2); while((price== (price*1.00)) && (itemnum == (itemnum*1))) { while (out_stream3 << itemnum << price) { while (out_stream3.eof()) // reads file to end of file { out_stream3 << itemnum; out_stream3 << price; price++; curr_total= price++; out_stream3 << curr_total; cin.clear(); // allows more reading cin >> next; } return itemnum, price; } } in_stream4.setf(ios::fixed); in_stream4.setf(ios::showpoint); in_stream4.precision(2); while ( in_stream4.eof()) { in_stream4 >> itemnum >> price >> curr_total; cin.clear(); cin >> next; } out_stream5.setf(ios::fixed); out_stream5.setf(ios::showpoint); out_stream5.precision(2); out_stream5 <<setw(5)<< " itemnum " <<setw(5)<<" price "<<setw(5)<<" curr_total " <<endl; // sends items and prices to receipt.txt out_stream5 << setw(5) << itemnum << setw(5) <<price << setw(5)<< curr_total; // sends items and prices to receipt.txt out_stream5 << " You have a total of " << wrong++ << " errors " << endl; }

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  • Why SetUnhandledExceptionFilter cannot capture some exception but AddVectoredExceptionHandler can do

    - by wrongite
    I have experienced a problem that the function I passed to the SetUnhandledExceptionFilter didn't get called when the exception code c0000374 raising. But it works fine with the exception code c0000005. Then I tried to use the AddVectoredExceptionHandler instead, and it didn't have the problem, the handler function get called correctly. Is it the API bug? Can I use AddVectoredExceptionHandler instead of SetUnhandledExceptionFilter everywhere? The both functions work correctly with // Exception code c0000005 int* p1 = NULL; *p1 = 99; Only AddVectoredExceptionHandler can capture this exception. // Exception code c0000374 int* p2 = new int; delete p2; delete p2; Test program. #include <tchar.h> #include <fstream> #include <Windows.h> LONG WINAPI VectoredExceptionHandler(PEXCEPTION_POINTERS pExceptionInfo) { std::ofstream f; f.open("VectoredExceptionHandler.txt", std::ios::out | std::ios::trunc); f << std::hex << pExceptionInfo->ExceptionRecord->ExceptionCode << std::endl; f.close(); return EXCEPTION_CONTINUE_SEARCH; } LONG WINAPI TopLevelExceptionHandler(PEXCEPTION_POINTERS pExceptionInfo) { std::ofstream f; f.open("TopLevelExceptionHandler.txt", std::ios::out | std::ios::trunc); f << std::hex << pExceptionInfo->ExceptionRecord->ExceptionCode << std::endl; f.close(); return EXCEPTION_CONTINUE_SEARCH; } int _tmain(int argc, _TCHAR* argv[]) { AddVectoredExceptionHandler(1, VectoredExceptionHandler); SetUnhandledExceptionFilter(TopLevelExceptionHandler); // Exception code c0000374 int* p2 = new int; delete p2; delete p2; // Exception code c0000005 int* p1 = NULL; *p1 = 99; return 0; }

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  • std::iostream link error vs2010 rc1

    - by Martin Beckett
    I'm converting a project from vs2008 to vs2010 and getting linker errors for std:ifstream/ofstream error LNK2001: unresolved external symbol "__declspec(dllimport) public: bool __thiscall std::basic_ofstream<char,struct std::char_traits<char> >::is_open(void)const " (__imp_?is_open@?$basic_ofstream@DU?$char_traits@D@std@@@std@@QBE_NXZ) Building static (/MT) or dll (/MD) with unicode or standard and release/debug gives the same error. Manually adding libcpmtd.lib (static) or msvcprtd.lib (dll) to the linker doesn't help. Has anyone else seen this?

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  • C++ simple logging class with UTF-8 output [code example]

    - by Andrew
    Hello everyone, I was working on one of my academic projects and for the first time I needed pure C++ without GUI. After googling for a while, I did not find any simple and easy to use implementation for logging and created my own. This is a simple implementation with iostreams that logs messages to screen and to the file simultaneously. I was thinking of using templates but then I realized that I do not expect any changes and removed that. It is modified std::wostream with two added modifiers: 1. TimeStamp - prints time-stamp 2. LogMode(LogModes) - switches output: file only, screen only, file+screen. *Boost::utf8_codecvt_facet* is used for UTF-8 output. // ############################################################################ // # Name: MyLog.h # // # Purpose: Logging Class Header # // # Author: Andrew Drach # // # Modified by: <somebody> # // # Created: 03/21/10 # // # SVN-ID: $Id$ # // # Copyright: (c) 2010 Andrew Drach # // # Licence: <license> # // ############################################################################ #ifndef INCLUDED_MYLOG_H #define INCLUDED_MYLOG_H // headers -------------------------------------------------------------------- #include <string> #include <iostream> #include <fstream> #include <exception> #include <boost/program_options/detail/utf8_codecvt_facet.hpp> using namespace std; // definitions ---------------------------------------------------------------- // ---------------------------------------------------------------------------- // DblBuf class // Splits up output stream into two // Inspired by http://wordaligned.org/articles/cpp-streambufs // ---------------------------------------------------------------------------- class DblBuf : public wstreambuf { private: // private member declarations DblBuf(); wstreambuf *bf1; wstreambuf *bf2; virtual int_type overflow(int_type ch) { int_type eof = traits_type::eof(); int_type not_eof = !eof; if ( traits_type::eq_int_type(ch,eof) ) return not_eof; else { char_type ch1 = traits_type::to_char_type(ch); int_type r1( bf1on ? bf1->sputc(ch1) : not_eof ); int_type r2( bf2on ? bf2->sputc(ch1) : not_eof ); return (traits_type::eq_int_type(r1,eof) || traits_type::eq_int_type(r2,eof) ) ? eof : ch; } } virtual int sync() { int r1( bf1on ? bf1->pubsync() : NULL ); int r2( bf2on ? bf2->pubsync() : NULL ); return (r1 == 0 && r2 == 0) ? 0 : -1; } public: // public member declarations explicit DblBuf(wstreambuf *bf1, wstreambuf *bf2) : bf1(bf1), bf2(bf2) { if (bf1) bf1on = true; else bf1on = false; if (bf2) bf2on = true; else bf2on = false; } bool bf1on; bool bf2on; }; // ---------------------------------------------------------------------------- // logstream class // Wrapper for a standard wostream with access to modified buffer // ---------------------------------------------------------------------------- class logstream : public wostream { private: // private member declarations logstream(); public: // public member declarations DblBuf *buf; explicit logstream(wstreambuf *StrBuf, bool isStd = false) : wostream(StrBuf, isStd), buf((DblBuf*)StrBuf) {} }; // ---------------------------------------------------------------------------- // Logging mode Class // ---------------------------------------------------------------------------- enum LogModes{LogToFile=1, LogToScreen, LogToBoth}; class LogMode { private: // private member declarations LogMode(); short mode; public: // public member declarations LogMode(short mode1) : mode(mode1) {} logstream& operator()(logstream &stream1) { switch(mode) { case LogToFile: stream1.buf->bf1on = true; stream1.buf->bf2on = false; break; case LogToScreen: stream1.buf->bf1on = false; stream1.buf->bf2on = true; break; case LogToBoth: stream1.buf->bf1on = true; stream1.buf->bf2on = true; } return stream1; } }; logstream& operator<<(logstream &out, LogMode mode) { return mode(out); } wostream& TimeStamp1(wostream &out1) { time_t time1; struct tm timeinfo; wchar_t timestr[512]; // Get current time and convert it to a string time(&time1); localtime_s (&timeinfo, &time1); wcsftime(timestr, 512,L"[%Y-%b-%d %H:%M:%S %p] ",&timeinfo); return out1 << timestr; } // ---------------------------------------------------------------------------- // MyLog class // Logs events to both file and screen // ---------------------------------------------------------------------------- class MyLog { private: // private member declarations MyLog(); auto_ptr<DblBuf> buf; string mErrorMsg1; string mErrorMsg2; string mErrorMsg3; string mErrorMsg4; public: // public member declarations explicit MyLog(string FileName1, wostream *ScrLog1, locale utf8locale1); ~MyLog(); void NewEvent(wstring str1, bool TimeStamp = true); string FileName; wostream *ScrLog; wofstream File; auto_ptr<logstream> Log; locale utf8locale; }; // ---------------------------------------------------------------------------- // MyLog constructor // ---------------------------------------------------------------------------- MyLog::MyLog(string FileName1, wostream *ScrLog1, locale utf8locale1) : // ctors mErrorMsg1("Failed to open file for application logging! []"), mErrorMsg2("Failed to write BOM! []"), mErrorMsg3("Failed to write to file! []"), mErrorMsg4("Failed to close file! []"), FileName(FileName1), ScrLog(ScrLog1), utf8locale(utf8locale1), File(FileName1.c_str()) { // Adjust error strings mErrorMsg1.insert(mErrorMsg1.length()-1,FileName1); mErrorMsg2.insert(mErrorMsg2.length()-1,FileName1); mErrorMsg3.insert(mErrorMsg3.length()-1,FileName1); mErrorMsg4.insert(mErrorMsg4.length()-1,FileName1); // check for file open errors if ( !File ) throw ofstream::failure(mErrorMsg1); // write UTF-8 BOM File << wchar_t(0xEF) << wchar_t(0xBB) << wchar_t(0xBF); // switch locale to UTF-8 File.imbue(utf8locale); // check for write errors if ( File.bad() ) throw ofstream::failure(mErrorMsg2); buf.reset( new DblBuf(File.rdbuf(),ScrLog->rdbuf()) ); Log.reset( new logstream(&*buf) ); } // ---------------------------------------------------------------------------- // MyLog destructor // ---------------------------------------------------------------------------- MyLog::~MyLog() { *Log << TimeStamp1 << "Log finished." << endl; // clean up objects Log.reset(); buf.reset(); File.close(); // check for file close errors if ( File.bad() ) throw ofstream::failure(mErrorMsg4); } //--------------------------------------------------------------------------- #endif // INCLUDED_MYLOG_H Tested on MSVC 2008, boost 1.42. I do not know if this is the right place to share it. Hope it helps anybody. Feel free to make it better.

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  • Reading a large text file to memory in C++

    - by NoneType
    Is there a way to read a large text file (~60MB) into memory at once (like a compiler flag to increase program memory limit) ? Currently, ofstream's open function throws a segmentation fault while trying to read this file. ifstream fis; fis.open("my_large_file.txt"); // Segfaults here The file just consists of rows of the form number_1<tabspace>number_2 i.e., two numbers separated by a tabspace.

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  • Reading binary file with Octave

    - by Anthony Blake
    I'm trying to a binary file consisting of floats with Octave (on OS X), but I'm getting the following error: octave-3.2.3:2> load Input.dat R -binary error: load: failed to read matrix from file `Input.dat' The file was written like so: std::ofstream fout("Input.dat", std::ios::trunc | std::ios::binary); fout.write(reinterpret_cast<char*>(Buf), N*sizeof(double)); fout.close(); Any idea what could be going wrong here?

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  • Can AutoCAD entities be serialized?

    - by billmuell
    Using ObjectARX (C++) for AutoCAD 2010, can AutoCAD entities be serialized? We need to save the serialized entity in a field in a database (Oracle, PostgreSQL, etc., not AcDbDatabase). It'OK if you show me how to save them in disk, something like this: AcDbEntity * entity; ... std::ofstream ofs("c:\\filename.fil", std::ios::binary); ofs.write((char *)(entity), sizeof(entity)); ofs.close(); Thanks

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  • C++ write to front of file

    - by user231536
    I need to open a file as ofstream and write to the front of the file, while preserving the remaining contents of the file, which will be "moved". Similar to "prepend" a file. Is this possible using the STL or boost ?

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  • C++ question on file formats and od

    - by user231536
    I have the following simple code: ofstream output("test"); output << 'a'; When I do an octal dump of the file, I get this: 0000000 000141 0000001 I can see that 000141 (in base 8) is 8 bits wide and 0000001 is probably EOF. What is the first byte of all 0's and why is it there? I know it is null is ascii but what is its purpose?

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  • writing string into file before calling the close()

    - by navinbecse
    I am using ofstream() to write data into file, i want to program to perform such a way that it should be keep on writting the string into the file as soon as the value gets assingned to string variable, and it should be writting before calling the close() for the buffer and while the program runs itself. can anyone help me to do that in c++.........

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  • fatal error C1075: end of file found before the left brace and read and write files not working

    - by user320950
    could someone also tell me if the actions i am attempting to do which are stated in the comments are correct or not. i am new at c++ and i think its correct but i have doubts #include<iostream> #include<fstream> #include<cstdlib> #include<iomanip> using namespace std; int main() { ifstream in_stream; // reads itemlist.txt ofstream out_stream1; // writes in items.txt ifstream in_stream2; // reads pricelist.txt ofstream out_stream3;// writes in plist.txt ifstream in_stream4;// read recipt.txt ofstream out_stream5;// write display.txt float price=' ',curr_total=0.0; int wrong=0; int itemnum=' '; char next; in_stream.open("ITEMLIST.txt", ios::in); // list of avaliable items if( in_stream.fail() )// check to see if itemlist.txt is open { wrong++; cout << " the error occured here0, you have " << wrong++ << " errors" << endl; cout << "Error opening the file\n" << endl; exit(1); } else{ cout << " System ran correctly " << endl; out_stream1.open("listWititems.txt", ios::out); // list of avaliable items if(out_stream1.fail() )// check to see if itemlist.txt is open { wrong++; cout << " the error occured here1, you have " << wrong++ << " errors" << endl; cout << "Error opening the file\n"; exit(1); } else{ cout << " System ran correctly " << endl; } in_stream2.open("PRICELIST.txt", ios::in); if( in_stream2.fail() ) { wrong++; cout << " the error occured here2, you have " << wrong++ << " errors" << endl; cout << "Error opening the file\n"; exit (1); } else{ cout << " System ran correctly " << endl; } out_stream3.open("listWitdollars.txt", ios::out); if(out_stream3.fail() ) { wrong++; cout << " the error occured here3, you have " << wrong++ << " errors" << endl; cout << "Error opening the file\n"; exit (1); } else{ cout << " System ran correctly " << endl; } in_stream4.open("display.txt", ios::in); if( in_stream4.fail() ) { wrong++; cout << " the error occured here4, you have " << wrong++ << " errors" << endl; cout << "Error opening the file\n"; exit (1); } else{ cout << " System ran correctly " << endl; } out_stream5.open("showitems.txt", ios::out); if( out_stream5.fail() ) { wrong++; cout << " the error occured here5, you have " << wrong++ << " errors" << endl; cout << "Error opening the file\n"; exit (1); } else{ cout << " System ran correctly " << endl; } in_stream.close(); // closing files. out_stream1.close(); in_stream2.close(); out_stream3.close(); in_stream4.close(); out_stream5.close(); system("pause"); in_stream.setf(ios::fixed); while(in_stream.eof()) { in_stream >> itemnum; cin.clear(); cin >> next; } out_stream1.setf(ios::fixed); while (out_stream1.eof()) { out_stream1 << itemnum; cin.clear(); cin >> next; } in_stream2.setf(ios::fixed); in_stream2.setf(ios::showpoint); in_stream2.precision(2); while((price== (price*1.00)) && (itemnum == (itemnum*1))) { while (in_stream2 >> itemnum >> price) // gets itemnum and price { while (in_stream2.eof()) // reads file to end of file { in_stream2 >> itemnum; in_stream2 >> price; price++; curr_total= price++; in_stream2 >> curr_total; cin.clear(); // allows more reading cin >> next; } } } out_stream3.setf(ios::fixed); out_stream3.setf(ios::showpoint); out_stream3.precision(2); while((price== (price*1.00)) && (itemnum == (itemnum*1))) { while (out_stream3 << itemnum << price) { while (out_stream3.eof()) // reads file to end of file { out_stream3 << itemnum; out_stream3 << price; price++; curr_total= price++; out_stream3 << curr_total; cin.clear(); // allows more reading cin >> next; } return itemnum, price; } } in_stream4.setf(ios::fixed); in_stream4.setf(ios::showpoint); in_stream4.precision(2); while ( in_stream4.eof()) { in_stream4 >> itemnum >> price >> curr_total; cin.clear(); cin >> next; } out_stream5.setf(ios::fixed); out_stream5.setf(ios::showpoint); out_stream5.precision(2); out_stream5 <<setw(5)<< " itemnum " <<setw(5)<<" price "<<setw(5)<<" curr_total " <<endl; // sends items and prices to receipt.txt out_stream5 << setw(5) << itemnum << setw(5) <<price << setw(5)<< curr_total; // sends items and prices to receipt.txt out_stream5 << " You have a total of " << wrong++ << " errors " << endl; }

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  • i see the file but when i open it nothing is in it in c++ i/o stream and dont know why

    - by user320950
    #include<iostream> #include<fstream> #include<cstdlib> #include<iomanip> using namespace std; int main() { ifstream in_stream; // reads ITEMSLIST.txt ofstream out_stream1; // writes in listWititems.txt ifstream in_stream2; // reads PRICELIST.txt ofstream out_stream3;// writes in listWitprices.txt ifstream in_stream4;// read display.txt ofstream out_stream5;// write showitems.txt double p1=0.0,p2=0.0; int wrong=0; int count =0; char next; in_stream.open("ITEMLIST.txt", ios::in); // list of avaliable items /*if( in_stream.fail() )// check to see if itemlist.txt is open { wrong++; // counts number of errors cout << " the error occured here0, you have " << wrong++ << " errors" << endl; cout << "Error opening the file\n" << endl; exit(1); } else{ cout << " System ran correctly " << endl; } */ out_stream1.open("listWititems.txt", ios::out); // list of avaliable items /* if( out_stream1.fail() )// check to see if itemlist.txt is open { wrong++; cout << " the error occured here0, you have " << wrong++ << " errors" << endl; cout << "Error opening the file\n" << endl; exit(1); } else{ cout << " System ran correctly " << endl; } */ in_stream2.open("PRICELIST.txt", ios::in); /*if( in_stream2.fail() )// check to see if itemlist.txt is open { wrong++; cout << " the error occured here0, you have " << wrong++ << " errors" << endl; cout << "Error opening the file\n" << endl; exit(1); } else{ cout << " System ran correctly " << endl; } */ out_stream3.open("listWitdollars.txt", ios::out); /*if( out_stream3.fail() )// check to see if itemlist.txt is open { wrong++; cout << " the error occured here0, you have " << wrong++ << " errors" << endl; cout << "Error opening the file\n" << endl; exit(1); } else{ cout << " System ran correctly " << endl; } */ in_stream4.open("display.txt", ios::in); /*if( in_stream4.fail() )// check to see if itemlist.txt is open { wrong++; cout << " the error occured here0, you have " << wrong++ << " errors" << endl; cout << "Error opening the file\n" << endl; exit(1); } else{ cout << " System ran correctly " << endl; } */ out_stream5.open("showitems.txt", ios::out); /*if( out_stream5.fail() )// check to see if itemlist.txt is open { wrong++; cout << " the error occured here0, you have " << wrong++ << " errors" << endl; cout << "Error opening the file\n" << endl; exit(1); } else{ cout << " System ran correctly " << endl; }*/ in_stream.setf(ios::fixed); while(!in_stream.eof()) // reads to end of file and gets p1 which is itemnum, clears and gets next character { in_stream >> p1; cin.clear(); cin >> next; } out_stream1.setf(ios::fixed); while (!out_stream1.eof()) { out_stream1 << p1; cin.clear(); cin >> next; } in_stream2.setf(ios::fixed); in_stream2.setf(ios::showpoint); in_stream2.precision(2); while(!in_stream2.eof()) // reads file to end of file { in_stream2 >> p1 >> p2 >> count; // gets p1,p2, and count which is current total in_stream2 >> p2; p1 += p2; p2++; cin.clear(); // allows more reading cin >> next; return p1, p2; } out_stream3.setf(ios::fixed); out_stream3.setf(ios::showpoint); out_stream3.precision(2); while(!out_stream3.eof()) // reads file to end of file { out_stream3 << p1 << p2 << count; out_stream3 << p2; p1 += p2; p2++; cin.clear(); // allows more reading cin >> next; return p1, p2; } in_stream4.setf(ios::fixed); in_stream4.setf(ios::showpoint); in_stream4.precision(2); while (!in_stream4.eof()) { in_stream4 >> p1 >> p2 >> count; cin.clear(); cin >> next; } out_stream5.setf(ios::fixed); out_stream5.setf(ios::showpoint); out_stream5.precision(2); out_stream5 <<setw(5)<< " itemnum " <<setw(5)<<" price "<<setw(5)<<" curr_total " <<endl; // sends items and prices to receipt.txt out_stream5 << setw(5) << p1 << setw(5) <<p2 << setw(5)<< count; // sends items and prices to receipt.txt out_stream5 << " You have a total of " << wrong++ << " errors " << endl; in_stream.close(); // closing files. out_stream1.close(); in_stream2.close(); out_stream3.close(); in_stream4.close(); out_stream5.close(); system("pause"); }

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  • I’m new to C++ and unsure about how to improve this code [migrated]

    - by Laian Alsabbagh
    The purpose of the following code is to get a random number of 100 nodes and to distribute these nodes randomly in range 500*500 …(X,Y).. this was the first step #include<iostream> #include <fstream> #include<cmath> using namespace std; int main() { const int x = 0, y = 1; int nodes[100][2]; ofstream myfile; myfile.open ("example.txt"); myfile << "Writing this to a file.\n"; for (int i=0; i<100 ;i++) { nodes[i][x] = rand() % 501; nodes[i][y] = rand() % 501; myfile <<nodes[i][x]<<" "<<nodes[i][y]; } myfile.close(); } now the next step is to improve this code to distribute these nodes in order ( "Imust divide both xy_coordinates as : x= 0-100-200-300-400-500 & y=0-100-200-300-400-500) next is to distribute the nodes (regardless number of nodes) in order range Starting from (0,100 )….(100,100)..(100,200)…….untile i reach the last point (500,500),, ") I’m really confused of how to do it correctly I start to think to define 2 dimensional array , and then to define 2 for loops enter code here Int no_nodes=100; Int XY_coordinate [500][500]; For (int i=0;i<no_nodes; i++) { For (int j=0;j<no_nodes; j++)

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  • 1>Project : error PRJ0003 : Error spawning 'rc.exe'.

    - by user320950
    1Project : error PRJ0003 : Error spawning 'rc.exe'.. this is the error i get when i try to run this small practice program of reading and writing files which i cant do because of the reason of me not being able to get the files to open correctly. i use microsoft visual c++ 2008 and i have used the file path to try to open the file as well and i cant can someone help? #include <iostream> #include <fstream> using namespace std; int main () { ifstream infile; ofstream myfile; infile.open("ex.txt"); myfile.open ("example.txt"); myfile.close(); return 0; }

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  • Fastest way to write large STL vector to file using STL

    - by ljubak
    I have a large vector (10^9 elements) of chars, and I was wondering what is the fastest way to write such vector to a file. So far I've been using next code: vector<char> vs; // ... Fill vector with data ofstream outfile("nanocube.txt", ios::out | ios::binary); ostream_iterator<char> oi(outfile, '\0'); copy(vs.begin(), vs.end(), oi); For this code it takes approximately two minutes to write all data to file. The actual question is: "Can I make it faster using STL and how"?

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  • Compilation error when using boost serialization library

    - by Shakir
    I have been struggling with this error for a long time. The following is my code snippet. //This is the header file template<typename TElem> class ArrayList { public: /** An accessible typedef for the elements in the array. */ typedef TElem Elem; friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & ptr_; ar & size_; ar & cap_; } Elem *ptr_; // the stored or aliased array index_t size_; // number of active objects index_t cap_; // allocated size of the array; -1 if alias }; template <typename TElem> class gps_position { public: typedef TElem Elem; friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & degrees; ar & minutes; ar & seconds; } private: Elem degrees; index_t minutes; index_t seconds; }; // This is the .cc file #include #include #include #include #include #include #include #include #include "arraylist.h" int main() { // create and open a character archive for output std::ofstream ofs("filename"); // create class instance // gps_position<int> g(35.65, 59, 24.567f); gps_position<float> g; // save data to archive { boost::archive::text_oarchive oa(ofs); // write class instance to archive //oa << g; // archive and stream closed when destructors are called } // ... some time later restore the class instance to its orginal state /* gps_position<int> newg; { // create and open an archive for input std::ifstream ifs("filename"); boost::archive::text_iarchive ia(ifs); // read class state from archive ia >> newg; // archive and stream closed when destructors are called }*/ ArrayList<float> a1; ArrayList<int> a2; a1.Init(22); a2.Init(21); // a1.Resize(30); // a1.Resize(12); // a1.Resize(22); // a2.Resize(22); a1[21] = 99.0; a1[20] = 88.0; for (index_t i = 0; i < a1.size(); i++) { a1[i] = i; a1[i]++; } std::ofstream s("test.txt"); { boost::archive::text_oarchive oa(s); oa << a1; } return 0; } The following is the compilation error i get. In file included from /usr/include/boost/serialization/split_member.hpp:23, from /usr/include/boost/serialization/nvp.hpp:33, from /usr/include/boost/serialization/serialization.hpp:17, from /usr/include/boost/archive/detail/oserializer.hpp:61, from /usr/include/boost/archive/detail/interface_oarchive.hpp:24, from /usr/include/boost/archive/detail/common_oarchive.hpp:20, from /usr/include/boost/archive/basic_text_oarchive.hpp:32, from /usr/include/boost/archive/text_oarchive.hpp:31, from demo.cc:4: /usr/include/boost/serialization/access.hpp: In static member function ‘static void boost::serialization::access::serialize(Archive&, T&, unsigned int) [with Archive = boost::archive::text_oarchive, T = float]’: /usr/include/boost/serialization/serialization.hpp:74: instantiated from ‘void boost::serialization::serialize(Archive&, T&, unsigned int) [with Archive = boost::archive::text_oarchive, T = float]’ /usr/include/boost/serialization/serialization.hpp:133: instantiated from ‘void boost::serialization::serialize_adl(Archive&, T&, unsigned int) [with Archive = boost::archive::text_oarchive, T = float]’ /usr/include/boost/archive/detail/oserializer.hpp:140: instantiated from ‘void boost::archive::detail::oserializer<Archive, T>::save_object_data(boost::archive::detail::basic_oarchive&, const void*) const [with Archive = boost::archive::text_oarchive, T = float]’ demo.cc:105: instantiated from here /usr/include/boost/serialization/access.hpp:109: error: request for member ‘serialize’ in ‘t’, which is of non-class type ‘float’ Please help me out.

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  • how to serialize / deserialize classes defined in .proto (protobuf)

    - by make
    Hi, Could someone please help me with serialization/deserialization classes defined in .proto (protobuf). here is an exp that I am trying to build: file.proto message Data{ required string x1 = 1; required uint32 x2 = 2; required float x3 = 3; } message DataExge { repeated Data data = 1; } client.cpp ... void serialize(const DataExge &data_snd){ try { ofstream ofs("DataExge"); data_snd.SerializeToOstream(&ofs); } catch(exception &e) { cerr << "serialize/exception: " << e.what() << endl; exit(1); } } void deserialize(DataExge &data_rec){ try { ifstream ifs("DataExge"); data_rec.ParseFromIstream(&ifs); } catch(exception& e) { cerr << "deserialize/exception: " << e.what() << endl; exit(1); } } int main(){ ... DataExge dataexge; Data *dat = dataexge.add_data(); char *y1 = "operation1"; uint32_t y2 = 123 ; float y3 = 3.14; // assigning data to send() dat->set_set_x1(y1); dat->set_set_x2(y2); dat->set_set_x3(y3); //sending data to the client serialize(dataexge); if (send(socket, &dataexge, sizeof(dataexge), 0) < 0) { cerr << "send() failed" ; exit(1); } //receiving data from the server deserialize(dataexge); if (recv(socket, &dataexge, sizeof(dataexge), 0) < 0) { cerr << "recv() failed"; exit(1); } //printing received data cout << dat->x1() << "\n"; cout << dat->x2() << "\n"; cout << dat->x3() << "\n"; ... } server.cpp ... void serialize(const DataExge &data_snd){ try { ofstream ofs("DataExge"); data_snd.SerializeToOstream(&ofs); } catch(exception &e) { cerr << "serialize/exception: " << e.what() << endl; exit(1); } } void deserialize(DataExge &data_rec){ try { ifstream ifs("DataExge"); data_rec.ParseFromIstream(&ifs); } catch(exception& e) { cerr << "deserialize/exception: " << e.what() << endl; exit(1); } } int main(){ ... DataExge dataexge; Data *dat = dataexge.add_data(); //receiving data from the client deserialize(dataexge); if (recv(socket, &dataexge, sizeof(dataexge), 0) < 0) { cerr << "recv() failed"; exit(1); } //printing received data cout << dat->x1() << "\n"; cout << dat->x2() << "\n"; cout << dat->x3() << "\n"; // assigning data to send() dat->set_set_x1("operation2"); dat->set_set_x2(dat->x2() + 1); dat->set_set_x3(dat->x3() + 1.1); //sending data to the client serialize(dataexge); //error// I am getting error at this line ... if (send(socket, &dataexge, sizeof(dataexge), 0) < 0) { cerr << "send() failed" ; exit(1); } ... } Thanks for your help and replies -

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  • dynamic array pointer to binary file

    - by Yijinsei
    Hi guys, Know this might be rather basic, but I been trying to figure out how to one after create a dynamic array such as double* data = new double[size]; be used as a source of data to be kept in to a binary file such as ofstream fs("data.bin",ios:binary"); fs.write(reinterpret_cast<const char *> (data),size*sizeof(double)); When I finish writing, I attempt to read the file through double* data = new double[size]; ifstream fs("data.bin",ios:binary"); fs.read(reinterpret_cast<char*> (data),size*sizeof(double)); However I seem to encounter a run time error when reading the data. Do you guys have any advice how i should attempt to write a dynamic array using pointers passed from other methods to be stored in binary files?

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  • Singleton code linker errors in vc 9.0. Runs fine in linux compiled with gcc

    - by user306560
    I have a simple logger that is implemented as a singleton. It works like i want when I compile and run it with g++ in linux but when I compile in Visual Studio 9.0 with vc++ I get the following errors. Is there a way to fix this? I don't mind changing the logger class around, but I would like to avoid changing how it is called. 1>Linking... 1>loggerTest.obj : error LNK2005: "public: static class Logger * __cdecl Logger::getInstance(void)" (?getInstance@Logger@@SAPAV1@XZ) already defined in Logger.obj 1>loggerTest.obj : error LNK2005: "public: void __thiscall Logger::log(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (?log@Logger@@QAEXABV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z) already defined in Logger.obj 1>loggerTest.obj : error LNK2005: "public: void __thiscall Logger::closeLog(void)" (?closeLog@Logger@@QAEXXZ) already defined in Logger.obj 1>loggerTest.obj : error LNK2005: "private: static class Logger * Logger::_instance" (?_instance@Logger@@0PAV1@A) already defined in Logger.obj 1>Logger.obj : error LNK2001: unresolved external symbol "private: static class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > Logger::_path" (?_path@Logger@@0V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@A) 1>loggerTest.obj : error LNK2001: unresolved external symbol "private: static class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > Logger::_path" (?_path@Logger@@0V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@A) 1>Logger.obj : error LNK2001: unresolved external symbol "private: static class boost::mutex Logger::_mutex" (?_mutex@Logger@@0Vmutex@boost@@A) 1>loggerTest.obj : error LNK2001: unresolved external symbol "private: static class boost::mutex Logger::_mutex" (?_mutex@Logger@@0Vmutex@boost@@A) 1>Logger.obj : error LNK2001: unresolved external symbol "private: static class std::basic_ofstream<char,struct std::char_traits<char> > Logger::_log" (?_log@Logger@@0V?$basic_ofstream@DU?$char_traits@D@std@@@std@@A) 1>loggerTest.obj : error LNK2001: unresolved external symbol "private: static class std::basic_ofstream<char,struct std::char_traits<char> > Logger::_log" (?_log@Logger@@0V?$basic_ofstream@DU?$char_traits@D@std@@@std@@A) The code, three files Logger.h Logger.cpp test.cpp #ifndef __LOGGER_CPP__ #define __LOGGER_CPP__ #include "Logger.h" Logger* Logger::_instance = 0; //string Logger::_path = "log"; //ofstream Logger::_log; //boost::mutex Logger::_mutex; Logger* Logger::getInstance(){ { boost::mutex::scoped_lock lock(_mutex); if(_instance == 0) { _instance = new Logger; _path = "log"; } } //mutex return _instance; } void Logger::log(const std::string& msg){ { boost::mutex::scoped_lock lock(_mutex); if(!_log.is_open()){ _log.open(_path.c_str()); } if(_log.is_open()){ _log << msg.c_str() << std::endl; } } } void Logger::closeLog(){ Logger::_log.close(); } #endif ` ... #ifndef __LOGGER_H__ #define __LOGGER_H__ #include <iostream> #include <string> #include <fstream> #include <boost/thread/mutex.hpp> #include <boost/thread.hpp> using namespace std; class Logger { public: static Logger* getInstance(); void log(const std::string& msg); void closeLog(); protected: Logger(){} private: static Logger* _instance; static string _path; static bool _logOpen; static ofstream _log; static boost::mutex _mutex; //check mutable }; #endif test.cpp ` #include <iostream> #include "Logger.cpp" using namespace std; int main(int argc, char *argv[]) { Logger* log = Logger::getInstance(); log->log("hello world\n"); return 0; }

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  • mmap() for large file I/O?

    - by Boatzart
    I'm creating a utility in C++ to be run on Linux which can convert videos to a proprietary format. The video frames are very large (up to 16 megapixels), and we need to be able to seek directly to exact frame numbers, so our file format uses libz to compress each frame individually, and append the compressed data onto a file. Once all frames are finished being written, a journal which includes meta data for each frame (including their file offsets and sizes) is written to the end of the file. I'm currently using ifstream and ofstream to do the file i/o, but I am looking to optimize as much as possible. I've heard that mmap() can increase performance in a lot of cases, and I'm wondering if mine is one of them. Our files will be in the tens to hundreds of gigabytes, and although writing will always be done sequentially, random access reads should be done in constant time. Any thoughts as to whether I should investigate this further, and if so does anyone have any tips for things to look out for? Thanks!

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  • Connecting std::basic_ofstream<unsigned char> to a FIFO. bad_cast exceptions

    - by Mike B
    Using gcc 4.4.3 on Linux 2.6.32, I get bad_cast exceptions when connecting std::basic_ofstream to a FIFO. Stepping though the debugger, I can see that the error is generated at various places in the standard library because the _M_codecvt member of the stream or filebuf object is NULL. Exactly where it happens depends on the order of operations, but it appears to be the same cause in each. So am I doing something fundamentally stupid here? ofstream and ifstream work fine. Is there some reason that you shouldn't attach a stream of anything besides char to a FIFO? Thanks in advance.

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  • Writing booleans to file

    - by Sara
    Hello, I have a piece of code that gives a runtime error. Can anyone help find out why? vector<int> intData; vector<bool> boolData; for(int i=0;i<19000;i++) boolData.push_back(false); string ofile = "tree.dat"; ofstream fout(ofile.c_str(),ios::out | ios::binary); if (!boolData.empty()) fout.write((char *)&boolData[0], sizeof(bool)*boolData.size()); fout.close(); It gives the error when it tries to write the file (fout.write).

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  • C++ How do I properly use getline for ifstream members.

    - by John
    Ok so I have a problem with getline. I have a file that contains a couple strings. I created it by myself and I have each string on a seperate line. Ex. textfile.txt Line 1 Line 2 Line 3 Line 4 //Little snip of code ifstream inFile("textfile.txt"); getline(inFile, string1); When I debug the program and ask it to print out string1 it shows that "Line 1\r" is saved into string1. I understand that it's from me actually hitting enter when I created the file. This problem causes my program to have a segmentation fault. I know my code works because if I use ofstream to write the file first and then i read it in, it works. So for my quesiton, is their anyway to use the getline function without it picking up the escape sequence \r? If i am not clear just let me know.

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