doc/master/tree102__basic_8C.html

void tree102_basic()

{

   TString dir = gROOT->GetTutorialDir();

   dir.Append("/io/tree/");

   dir.ReplaceAll("/./", "/");


   auto f = TFile::Open("tree102.root", "RECREATE");

   auto h1 = new TH1F("h1", "x distribution", 100, -4, 4);

   auto T = new TTree("ntuple", "data from ascii file");

   Long64_t nlines = T->ReadFile(TString::Format("%sbasic.dat", dir.Data()), "x:y:z");

   printf(" found %lld points\n", nlines);

   T->Draw("x", "z>2");

   T->Write();

}

f
#define f(i)
Definition RSha256.hxx:104

Long64_t
long long Long64_t
Definition RtypesCore.h:69

gROOT
#define gROOT
Definition TROOT.h:406

TFile::Open
static TFile * Open(const char *name, Option_t *option="", const char *ftitle="", Int_t compress=ROOT::RCompressionSetting::EDefaults::kUseCompiledDefault, Int_t netopt=0)
Create / open a file.
Definition TFile.cxx:4086

TH1F
1-D histogram with a float per channel (see TH1 documentation)
Definition TH1.h:634

TString
Basic string class.
Definition TString.h:139

TString::Data
const char * Data() const
Definition TString.h:376

TString::ReplaceAll
TString & ReplaceAll(const TString &s1, const TString &s2)
Definition TString.h:704

TString::Append
TString & Append(const char *cs)
Definition TString.h:572

TString::Format
static TString Format(const char *fmt,...)
Static method which formats a string using a printf style format descriptor and return a TString.
Definition TString.cxx:2378

TTree
A TTree represents a columnar dataset.
Definition TTree.h:79

h1
TH1F * h1
Definition legend1.C:5