HepMC3 event record library
rootIO_example_read.cc
1 // -*- C++ -*-
2 //
3 // This file is part of HepMC
4 // Copyright (C) 2014-2019 The HepMC collaboration (see AUTHORS for details)
5 //
6 /**
7  * @example rootIO_example_read.cc
8  * @brief Basic example of use of root I/O: reading events from file
9  *
10  * @author Witold Pokorski
11  * @date 16/10/14
12  */
13 #include "HepMC3/GenEvent.h"
14 #include "HepMC3/WriterAscii.h"
15 #include "HepMC3/ReaderRoot.h"
16 #include "HepMC3/Print.h"
17 
18 #include <iostream>
19 
20 using namespace HepMC3;
21 
22 /** Main */
23 int main(int argc, char **argv) {
24 
25  if( argc<3 ) {
26  std::cout << "Usage: " << argv[0] << " <input_root_file> <output_hepmc3_file>" << std::endl;
27  exit(-1);
28  }
29 
30  ReaderRoot root_input (argv[1]);
31  WriterAscii text_output(argv[2]);
32 
33  int events_parsed = 0;
34 
35  while( !root_input.failed() ) {
36 
37  GenEvent evt;
38 
39  root_input.read_event(evt);
40 
41  if( root_input.failed() ) break;
42 
43  if( events_parsed == 0 ) {
44  std::cout << "First event: " << std::endl;
45  Print::listing(evt);
46  }
47 
48  text_output.write_event(evt);
49  ++events_parsed;
50 
51  if( events_parsed%100 == 0 ) {
52  std::cout << "Event: " << events_parsed << std::endl;
53  }
54  }
55 
56  root_input.close();
57  text_output.close();
58 
59  std::cout << "Events parsed and written: " << events_parsed << std::endl;
60 
61  return 0;
62 }
Definition of class WriterAscii.
static void listing(std::ostream &os, const GenEvent &event, unsigned short precision=2)
Print event in listing (HepMC2) format.
Definition: Print.cc:50
Definition of class ReaderRoot.
Stores event-related information.
Definition: GenEvent.h:41
int main(int argc, char **argv)
Definition of class GenEvent.
GenEvent I/O serialization for structured text files.
Definition: WriterAscii.h:25
GenEvent I/O parsing and serialization for root files.
Definition: ReaderRoot.h:32