doc/v618/basic2_8C.html

void basic2() {

   TString dir = gROOT->GetTutorialDir();

   dir.Append("/tree/");

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


   TFile *f = new TFile("basic2.root","RECREATE");

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

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

   Long64_t nlines = T->ReadFile(Form("%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:414

Form
char * Form(const char *fmt,...)

TFile
A ROOT file is a suite of consecutive data records (TKey instances) with a well defined format.
Definition: TFile.h:48

TH1F
1-D histogram with a float per channel (see TH1 documentation)}
Definition: TH1.h:571

TString
Basic string class.
Definition: TString.h:131

TString::Data
const char * Data() const
Definition: TString.h:364

TString::ReplaceAll
TString & ReplaceAll(const TString &s1, const TString &s2)
Definition: TString.h:687

TString::Append
TString & Append(const char *cs)
Definition: TString.h:559

TTree
A TTree represents a columnar dataset.
Definition: TTree.h:71

h1
TH1F * h1
Definition: legend1.C:5

ROOT::Math::Chebyshev::T
double T(double x)
Definition: ChebyshevPol.h:34