#include "Riostream.h"
#include "TFile.h"
#include "TH1.h"
#include "TNtuple.h"
#include "TF1.h"
void fithisto() 
{
ifstream in;
in.open(Form("Ro.dat"));
Float_t x,y;
Int_t nlines= 0;
TFile*f= new TFile("basic.root","RECREATE");
TH1F *h1 = new TH1F("h1","x distribution",3872.,128.5,5000.5);
TNtuple*ntuple= new TNtuple("ntuple","data from asciifile","x:y");
while (1) 
{
in >> x>> y;
if (!in.good()) break;
if (nlines< 5) 
printf("x=%8f, y=%8f",x,y);
h1->Fill(x,y);
ntuple->Fill(x,y);
nlines++;
}

TF1 *g1= new TF1("g1", "gaus",402.,430.);
TF1 *g2 = new TF1 ("g2", "gaus",1142.5,1210.5);
Double_t par[3];
g1->SetParameters(2800.,416.,1500.);
g2->SetParameters(1020,1178,1.7);
h1->Fit("g1","b");
h1->Fit("g2","b");
printf("found %dpoints\n",nlines);
in.close();
f->Write();
}