Author: Rene Brun
This notebook tutorial was automatically generated with ROOTBOOK-izer (Beta) from the macro found in the ROOT repository on Tuesday, January 17, 2017 at 02:42 PM.
In [1]:
%%cpp -d
#include "Riostream.h"
Read file $rootsys/tutorials/tree/basic.dat this file has 3 columns of float data
In [2]:
TString dir = gROOT->GetTutorialsDir();
dir.Append("/tree/");
dir.ReplaceAll("/./","/");
ifstream in;
in.open(Form("%sbasic.dat",dir.Data()));
Float_t x,y,z;
Int_t nlines = 0;
auto f = TFile::Open("basic.root","RECREATE");
TH1F h1("h1","x distribution",100,-4,4);
TNtuple ntuple("ntuple","data from ascii file","x:y:z");
while (1) {
in >> x >> y >> z;
if (!in.good()) break;
if (nlines < 5) printf("x=%8f, y=%8f, z=%8f\n",x,y,z);
h1.Fill(x);
ntuple.Fill(x,y,z);
nlines++;
}
printf(" found %d points\n",nlines);
in.close();
f->Write();