#include <iostream>
#include <vector>
#include <ROOT/RDataFrame.hxx>
#include <ROOT/RDFHelpers.hxx>
#include <ROOT/RResultPtr.hxx>
#include <TH2D.h>

using ROOT::RDF::RNode;

int main(int argc, char **argv)
{
  
  ROOT::RDataFrame df("tree2","testtree2.root");
  float a=5;
  auto df2 = df.Define("var_a", [a](){return a;});
   auto latestDF = std::make_unique<RNode>(df2);

   latestDF = std::make_unique<RNode>(latestDF->Define("A",[](){return 42;}));
   latestDF = std::make_unique<RNode>(latestDF->Define("B",[](){return 69;}));
   latestDF = std::make_unique<RNode>(latestDF->Define("C",[](){return 13;}));

   auto Total = latestDF->Count();
   std::cout <<"Total: "<<*Total<<std::endl;
  ROOT::RDF::SaveGraph(df,"graph2.dot");
  return 0;
};