/*
	IndexTest.cpp
	Compilation:  g++ -g IndexTest.cpp -I`root-config --incdir --libs` -o IndexTest
	Usage: IndexTest  FileName TreeName
*/

// C/C++ standard libs
#include <iostream>

// ROOT libs
#include <TFile.h>
#include <TTree.h>

const int NEv = 2;
const int NRun = 17;

int main(int argc, char** argv) {

	const char* SourceName = argv[1];     // source file name
	const char* SourceTreeName = argv[2]; // source ROOT tree names

	// get source file ready
	TFile OrigFile(SourceName, "READ"); // opens read only
	if (!OrigFile.IsOpen()) {
		std::cout << "Error: unable to open file " << SourceName << "." << std::endl;
		return 1;
	}

	TTree* pOrigTree = (TTree*) OrigFile.Get(SourceTreeName);
	if (!pOrigTree) {
		std::cout << "Unable to retrieve original tree - " << SourceName << "; content of the file:" << std::endl;
		OrigFile.ls();
		return 1;
	}

	std::cout << "Original tree " << pOrigTree->GetTitle()
		<< " in " << OrigFile.GetName() << " has " << pOrigTree->GetEntries() << " events." << std::endl;
	pOrigTree->Dump();

	std::cout << "Index of event " << NEv << " of run " << NRun << " = "
		<< pOrigTree->GetEntryNumberWithIndex(NRun, NEv) << std::endl;

	OrigFile.Close();

	return 0;
} // main()