## main111

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    // main111.cc is a part of the PYTHIA event generator.
    // Copyright (C) 2025 Torbjorn Sjostrand.
    // PYTHIA is licenced under the GNU GPL v2 or later, see COPYING for details.
    // Please respect the MCnet Guidelines, see GUIDELINES for details.

    // Keywords:
    //            Electron‑positron
    //            Basic usage
    //            Command file

    // This is a simple test program, equivalent with main103.cc,
    // but with data-base settings collected in a separate .cmnd file.
    // It studies the charged multiplicity distribution at LEP 1.

    #include "Pythia8/Pythia.h"

    using namespace Pythia8;

    //==========================================================================

    int main() {

      // Generator. Read in command file. Initialize.
      Pythia pythia;
      pythia.readFile("main111.cmnd");
      // If Pythia fails to initialize, exit with error.
      if (!pythia.init()) return 1;

      // Read number of events to generate. Book histogram.
      int nEvent = pythia.mode("Main:numberOfEvents");
      Hist mult("charged multiplicity", 100, -0.5, 99.5);

      // Begin event loop. Generate event. Skip if error.
      for (int iEvent = 0; iEvent < nEvent; ++iEvent) {
        if (!pythia.next()) continue;

        // Find number of all final charged particles and fill histogram.
        int nCharged = 0;
        for (int i = 0; i < pythia.event.size(); ++i)
          if (pythia.event[i].isFinal() && pythia.event[i].isCharged())
            ++nCharged;
        mult.fill( nCharged );

      // End of event loop. Statistics. Normalized histogram. Done.
      }
      pythia.stat();
      mult /= nEvent;
      cout << mult;
      return 0;
    }