HepMC Reference Documentation HepMC

example_ReadMyPythia.cc

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// garren@fnal.gov, October 2007
//  
// Read back the file written by example_MyPythia
// To Compile: go to the example directory and type:
// gmake example_ReadMyPythia.exe
//

#include <iostream>
#include <fstream>
#include "HepMC/IO_GenEvent.h"
#include "HepMC/GenEvent.h"

int main() { 
    //
    //........................................define an input scope
    {
        // open input stream
        std::ifstream istr( "example_MyPythia.dat" );
        if( !istr ) {
          std::cerr << "example_ReadMyPythia: cannot open example_MyPythia.dat" << std::endl;
          exit(-1);
        }
        HepMC::IO_GenEvent ascii_in(istr);
        // open output stream (alternate method)
        HepMC::IO_GenEvent ascii_out("example_MyPythia2.dat",std::ios::out);
        // now read the file
        int icount=0;
        HepMC::GenEvent* evt = ascii_in.read_next_event();
        while ( evt ) {
            icount++;
            if ( icount%50==1 ) std::cout << "Processing Event Number " << icount
                                          << " its # " << evt->event_number() 
                                          << std::endl;
            // write the event out to the ascii file
            ascii_out << evt;
            delete evt;
            ascii_in >> evt;
        }
        //........................................PRINT RESULT
        std::cout << icount << " events found. Finished." << std::endl;
    } // ascii_out and istr destructors are called here

    return 0;
}


 

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