void bar_hist()
{
//	input data
 	const Int_t nx = 8;
 	char *os_X[nx] = {"8","32","128","512","2048","8192","32768","131072"};
	float d_35_0[]= {0.75, -3.30, -0.92, 0.10, 0.08, -1.69, -1.29, -2.37};
	float d_35_1[]= {1.01, -3.02, -0.65, 0.37, 0.34, -1.42, -1.02, -2.10};
			
   	TCanvas *c1 = new TCanvas("rErrorC","",200,10,928,500);
   	c1->SetGrid(); c1->SetBottomMargin(0.1);
	c1->SetFillColor(10);  c1->SetBorderMode(0);

	gStyle->SetHistMinimumZero(kTRUE);

   	TH1F *h = new TH1F("h","",nx,0,nx);
   	h->SetFillColor(4);
	h->SetBarWidth(0.4); h->SetBarOffset(0.1); h->SetStats(0);
	h->SetMinimum(-5);
	h->SetMaximum(5);

	for (i=1;i<=nx;i++) {
		h->Fill(os_X[i-1], d_35_0[i-1]);
		h->GetXaxis()->SetBinLabel(i,os_X[i-1]);
	}
	
	h->Draw("bar1");

	TH1F *h2 = new TH1F("h","test",nx,0,nx);
	h2->SetFillColor(38);
	h2->SetBarWidth(0.4);
	h2->SetBarOffset(0.5);
	h2->SetStats(0);
	for (i=1;i<=nx;i++) {
		h2->Fill(os_X[i-1], d_35_1[i-1]);
	}
	h2->Draw("bar2,same");

	TLegend *leg = new TLegend(0.77184,0.833333,0.981501,0.927711);
	leg->SetTextSize(0.03); leg->SetBorderSize(2); leg->SetMargin(0.15);
	leg->SetFillColor(10);
	leg->AddEntry(h,"35.0","f");
	leg->AddEntry(h2,"35.1","f");
	leg->Draw();
}