Normalize THSatck

[Pepe_Le_Pew]

You could also try something like this:

// assuming that "MyTHStack" contains TH1F histograms ...
TH1F *h = new TH1F(*((TH1F *)(MyTHStack->GetStack()->Last())));
h->SetNameTitle("h", "my normalized stack");
h->Scale(1./h->Integral("width"));