Hello All,
I would like to draw one thing against another from an ascii file.
Therefore I wrote a little script that is included below.
My problem is, that the TTree->Draw() does not label the axes and I have
no idea how to label them (not the title but the numbers).
Thanks for your help
Stefan
#include <iostream>
#include <fstream>
#include <sstream>
#include <vector>
#include "Riostream.h"
#include <TFile.h>
#include <TH1F.h>
#include <TNtuple.h>
void reading(char infile[], Int_t nvals,
char draw[]="x[0]:x[1]", char selection[]=""){
// infile: ascii file to analyse
// nvals: Number of columns in the file
// draw: Draw option for TTree->Draw()
// selection: selection criterion for that
std::ifstream in;
in.open(infile);
Float_t* x = new Float_t[nvals];
Int_t nlines = 0;
std::ostringstream o;
o << "\"x[" << nvals << "]\"";
TTree *tree = new TTree("tree","data from file");
tree->Branch("x", x, o.str().c_str());
while (1) {
for(int i = 0; i < nvals; ++i )
in >> x[i];
if (!in.good()) break;
tree->Fill();
nlines++;
}
printf(" found %d points\n",nlines);
in.close();
tree->Draw(draw, selection, "hist", nlines, 0);
}
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