Superimpose two or more histograms from different files

From: <ntaddy_at_jlab.org>
Date: Mon, 24 Oct 2005 14:33:56 -0400 (EDT)

Dear rooters,

            I am a begginner in root and will be grateful if anyone could show me how to superimpose two or more histograms from different C++ macros, example: tb_9GeV_elec.C and tb_9GeV_pion.C all in the same directory. I have been able to execute these macros without any error, and display the histograms on a TCanvas which all came out nicely but now my problem is how to superimpose the two named histograms: h10 in tb_9GeV_elec.C and another h10 in tb_9GeV_pion.C. However, below is my key parts of my macro. Thank you all in advance for your assistance.
  I am working with root 4.02/02 on Linux machine. Regards,
Addy.

macro:tb_9GeV_elec.C, looks this
#include tb_elec2.C
#include "tb_9GeV_elec.h"
#include <TH2.h>
#include <TStyle.h>
#include <TCanvas.h>

void tb_9GeV_elec()
{
gStyle->SetCanvasBorderMode(0);
gStyle->SetPadBorderMode(0);
 char name0[80],
//Get Branches needed
tree->SetBranchesAddress("trk_nTrtHits", trk_nTrthits")  //Defining the Canvas

TCanvas *c1 = new TCanvas("c1", "electron track selection @9GeV, 50,50,600,800);
//Histograms
TH1F *h10 =new TH1F("HL electron per track", "nHL per electron track",30,0.,30.);
//Loop over hits
for (int hit=0;hit<trk_nTrrtHits[track];hit++) { if (sADC_C2>650){
h10->Fill(nhigh);
}
c1-cd();

h10-Draw();
h10->SetFillColor(7)
h10->SetXaxis()->SetTitle("nHL hit per track with cut")

c1->Update();
}

macro2 tb_9GeV_pion.C
I used the same macro but pion beam energy. macro:tb_9GeV_elec.C, looks this
#include tb_9GeV_pion.C
#include "tb_9GeV_pion.h"
#include <TH2.h>
#include <TStyle.h>
#include <TCanvas.h>

void tb_9GeV_pion()
{
gStyle->SetCanvasBorderMode(0);
gStyle->SetPadBorderMode(0);
 char name0[80],
//Get Branches needed
tree->SetBranchesAddress("trk_nTrtHits", trk_nTrthits")  //Defining the Canvas

TCanvas *c1 = new TCanvas("c1", "electron track selection @9GeV, 50,50,600,800);
//Histograms
TH1F *h10 =new TH1F("HL electron per track", "nHL per electron track",30,0.,30.);
//Loop over hits
for (int hit=0;hit<trk_nTrrtHits[track];hit++) { if (sADC_C2>650){
h10->Fill(nhigh);
}
c1-cd();

h10-Draw();
h10->SetFillColor(7)
h10->SetXaxis()->SetTitle("nHL hit per track with cut")

c1->Update();
} Received on Mon Oct 24 2005 - 20:34:04 MEST