// Divide and add 1D Histograms

void format_h(TH1F* h, int linecolor){
h->SetLineWidth(3);
h->SetLineColor(linecolor);
}

void macro6(){
TH1F* sig_h=new TH1F("sig_h","Signal Histo",50,0,10);
TH1F* gaus_h1=new TH1F("gaus_h1","Gauss Histo 1",30,0,10);
TH1F* gaus_h2=new TH1F("gaus_h2","Gauss Histo 2",30,0,10);
TH1F* bkg_h=new TH1F("exp_h","Exponential Histo",50,0,10);
// simulate the measurements
TRandom3 rndgen;
for (int imeas=0;imeas<4000;imeas++){
exp_h->Fill(rndgen.Exp(4));
if (imeas%4==0) gaus_h1->Fill(rndgen.Gaus(5,2));
if (imeas%4==0) gaus_h2->Fill(rndgen.Gaus(5,2));
if (imeas%10==0)sig_h->Fill(rndgen.Gaus(5,.5));}
// Format Histograms
TH1F* histos[4]={sig_h,bkg_h,gaus_h1,gaus_h2};
for (int i=0;i<4;++i){
histos[i]->Sumw2(); // *Very* Important
format_h(histos[i],i+1);
}
// Sum
TH1F* sum_h= new TH1F(*bkg_h);
sum_h->Add(sig_h,1.);
sum_h->SetTitle("Exponential + Gaussian");
format_h(sum_h,kBlue);
TCanvas* c_sum= new TCanvas();
sum_h->Draw("hist");
bkg_h->Draw("SameHist");
sig_h->Draw("SameHist");
// Divide
TH1F* dividend=new TH1F(*gaus_h1);
dividend->Divide(gaus_h2);
// Graphical Maquillage
dividend->SetTitle(";X axis;Gaus Histo 1 / Gaus Histo 2");
format_h(dividend,kOrange);
gaus_h1->SetTitle(";;Gaus Histo 1 and Gaus Histo 2");
gStyle->SetOptStat(0);
TCanvas* c_divide= new TCanvas();
c_divide->Divide(1,2,0,0);
c_divide->cd(1);
c_divide->GetPad(1)->SetRightMargin(.01);
gaus_h1->DrawNormalized("Hist");
gaus_h2->DrawNormalized("HistSame");

c_divide->cd(2);
dividend->GetYaxis()->SetRangeUser(0,2.49);
c_divide->GetPad(2)->SetGridy();
c_divide->GetPad(2)->SetRightMargin(.01);
dividend->Draw();
}