Drawing 2 TH1F in the same Canvas

Hello,
I would like to draw this 2 histos in the same canvas. This is my macro:

void prova()
{

   TCanvas *c1 = new TCanvas("c1", "c1",332,118,1584,958);
   TH1F *efficiency__1 = new TH1F("efficiency__1","efficiency__1",15,19.1,20.6);
   efficiency__1->SetBinContent(1,0.01673056);
   efficiency__1->SetBinContent(2,0.07371265);
   efficiency__1->SetBinContent(3,0.191641);
   efficiency__1->SetBinContent(4,0.3552014);
   efficiency__1->SetBinContent(5,0.5395277);
   efficiency__1->SetBinContent(6,0.6919468);
   efficiency__1->SetBinContent(7,0.8033561);
   efficiency__1->SetBinContent(8,0.8874251);
   efficiency__1->SetBinContent(9,0.9420324);
   efficiency__1->SetBinContent(10,0.9514549);
   efficiency__1->SetBinContent(11,0.9705836);
   efficiency__1->SetBinContent(12,0.9900967);
   efficiency__1->SetBinContent(13,0.9900967);
   efficiency__1->SetBinContent(14,0.9900967);
   efficiency__1->SetBinContent(15,1);
   efficiency__1->SetBinError(1,0.001);
   efficiency__1->SetBinError(2,0.001);
   efficiency__1->SetBinError(3,0.001);
   efficiency__1->SetBinError(4,0.001);
   efficiency__1->SetBinError(5,0.001);
   efficiency__1->SetBinError(6,0.001);
   efficiency__1->SetBinError(7,0.001);
   efficiency__1->SetBinError(8,0.001);
   efficiency__1->SetBinError(9,0.001);
   efficiency__1->SetBinError(10,0.001);
   efficiency__1->SetBinError(11,0.001);
   efficiency__1->SetBinError(12,0.001);
   efficiency__1->SetBinError(13,0.001);
   efficiency__1->SetBinError(14,0.001);
   efficiency__1->SetBinError(15,0.001);
   efficiency__1->SetEntries(15);

   TH1F *efficiency__2 = new TH1F("efficiency__2","efficiency__2",10,21,22);
   efficiency__2->SetBinContent(1,0.00268826);
   efficiency__2->SetBinContent(2,0.02686309);
   efficiency__2->SetBinContent(3,0.09620887);
   efficiency__2->SetBinContent(4,0.2070576);
   efficiency__2->SetBinContent(5,0.4293205);
   efficiency__2->SetBinContent(6,0.6432794);
   efficiency__2->SetBinContent(7,0.7854072);
   efficiency__2->SetBinContent(8,0.9302788);
   efficiency__2->SetBinContent(9,0.9721785);
   efficiency__2->SetBinContent(10,0.9921357);
   efficiency__2->SetBinError(1,0.0007575491);
   efficiency__2->SetBinError(2,0.002342859);
   efficiency__2->SetBinError(3,0.004482975);
   efficiency__2->SetBinError(4,0.005991573);
   efficiency__2->SetBinError(5,0.0078623);
   efficiency__2->SetBinError(6,0.008411869);
   efficiency__2->SetBinError(7,0.008374567);
   efficiency__2->SetBinError(8,0.007578031);
   efficiency__2->SetBinError(9,0.007437877);
   efficiency__2->SetBinError(10,0.007258875);
   efficiency__2->SetEntries(10);
   
   efficiency__1->Draw();
   efficiency__2->Draw("same");
   c1->Modified();
   c1->Update();
}

Thanks!

The way you did it is ok if the 2nd histogram range is inside the 1st one. If not, you will need to use THStack (option “nostack”).