/***************************************************************************
 * --------------------------------------------------------------------------
 * Template to exercise ROOT Introduction
 * -> Plot a normalized Gaussian with mean = 5.0 and sigma = 1.5
 *    and its derivative and integral in the range of 0 to 10
 * --------------------------------------------------------------------------
 * 13.06.2005, Klaus Rabbertz
 *
 * modification log:
 * kr, 28.06.2006: Removed explicit ex09 naming
 * as, 06.06.2008: Some small modifications
 * gq, 16.12.2010: small addition
 ***************************************************************************/

/* Note that this file can be either used as a compiled program
 * or as a ROOT macro.
 * If it is used as a compiled program, additional include statements
 * and the definition of the main program have to be made. This is 
 * not needed if the code is used as a macro.
 */

#ifndef __CINT__      // These include-statements are needed if the program is
#include "TFile.h"    // run as a "stand-alone application", i.e. if it is not 
#include "TCanvas.h"  // called from an interactive ROOT session.
#include "TF1.h"
#include "TMath.h"
#include <math.h>

void gauss();

//______________________________________________________________________________
int main()
{
  gauss();
  return 0;
}
#endif                 

//______________________________________________________________________________

// From here on, the code can also be used as a macro
// Note though, that CINT may report errors where there are none
// in C++. E.g. this happens here where CINT says that f1 is
// out of scope ...

// Define a new one-dimensional function of x[0], ngauss,
// with two parameters par[0] and par[1] representing the mean
// and standard deviation
Double_t ngauss(Double_t *x, Double_t *par) {
  
  Double_t val = TMath::Pi(); 
  return val;
}

void gauss() {

  /* Create a new ROOT binary machine independent file.
   * Note that this file may contain any kind of ROOT objects, histograms,
   * pictures, graphics objects, detector geometries, tracks, events, etc..
   * But only histograms and trees are written by default.
   * This file is now becoming the current directory.
   */
  TFile *f1 = new TFile("gauss.root","RECREATE","ROOT_Introduction");

  // Create a new canvas and divide it up into 2 x 2 pads
  TCanvas* c1 = new TCanvas("c1","c1",-700,500);
  c1->Divide(2,2);
  
  // Version 1
  // Create a new one-dimensional function myng1 in the limits 0 ... 10
  // with two parameters
  //TF1 *myng1 = new TF1("myng1",ngauss, ... );
  
  // Set the corresponding mean and sigma to 5.0 and 1.5
  // Use SetParameters and SetParNames for this
  
  // Version 2
  // Create a new one-dimensional function myng2 in the limits 0 ... 10
  // with the two parameters [0] and [1] 
  //TF1 *myng2 = new TF1("myng2","1/sqrt(2*pi)/[1]*exp((x-[0])/[1])^2)" ? ,...);

  // Set the corresponding mean and sigma to 5.0 and 1.5
  // Use SetParameters and SetParNames for this

  // Goto first pad and draw function version 1
  c1->cd(1);
  //myng1->Draw();
  
  // Goto second pad and draw function version 2
  c1->cd(2);
  //myng2->Draw();

  // Goto third pad and draw derivative of version 1
  c1->cd(3);
  //myng1->Draw???();

  // Goto fourth pad and draw integral of version 2
  c1->cd(4);
  //myng2->Draw???();
  
  // Save canvas (by default this is not done!)
  c1->Write();
  
  // Save other objects (histograms and trees by default) in this file
  f1->Write();
  
  // Close the file. Note that this is automatically done when you leave
  // the application.
  f1->Close();
}