//This macro shows how to divide and add 1D histograms. Based on ROOT 5 primer page number 33 (5.2)

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

void histexample3() {
	//four histograms
	TH1F* sig_h = new TH1F("sig_h","Signal Histogram",50,0,10);
	TH1F* gaus_h1 = new TH1F("gaus_h1","Gaus Histogram 1",30, 0, 10);
	TH1F* gaus_h2 = new TH1F("gaus_h2", "Gaus Histogram 2", 30,0,10);
	TH1F* bkg_h = new TH1F("exp_h", "Exponential Histogram",50,0,10);
	
	
	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* histograms[4] = {sig_h,bkg_h,gaus_h1,gaus_h2};
	for (int i = 0; i<4;++i){
		histograms[i]->Sumw2();
		format_hist(histograms[i],i+1);
	}
	
	//Sum of histograms
	TH1F* sum_h = new TH1F(*bkg_h);
	sum_h->Add(sig_h,1.);
	sum_h->SetTitle("Exponential + Gaussian");
	format_hist(sum_h,kBlue);
	
	TCanvas* c_sum = new TCanvas();
	sum_h->Draw("hist");
	bkg_h->Draw("SameHist");
	sig_h->Draw("SameHist");
	

}