How To Get Number of Bins?


I have a root file That I access like so:

TFile *file_in1 = new TFile("input.root", "READ");
	TNtuple *t1 = (TNtuple*)file_in1->Get("ntuple2");
	float ntuple2[4] = { 0 };

	t1->SetBranchAddress("x", &ntuple2[0]);
	t1->SetBranchAddress("y", &ntuple2[1]);
	t1->SetBranchAddress("t", &ntuple2[2]);
	t1->SetBranchAddress("N", &ntuple2[3]);
	int N_enteries_t1 = int(t1->GetEntries());

here is how does the root file look that I am reading:

I want to construct from this a new TH3 Histogram and fill it with data from the root file and I did that like this:( not sure if this is a right way though, correct me if it’s not)

TH3D *Kaon = new TH3D("kaon", "Kaon_test", 80, -0.5, 799.5, 12, -0.5, 127.5, 56, 12., 26.);

for (int i = 0; i < N_enteries_t1; i++)
		Kaon->Fill(ntuple2[0], ntuple2[1],ntuple2[2]);

what I want is to divide this histogram by the number of bins N to get pdf/normalize it.
how can I get the number of bins of ntuple[3]?
and then how can I divide the histogram with that number?


Kaon->Fill(ntuple2[0], ntuple2[1], ntuple2[2], (ntuple2[3] ? (1.0 / ntuple2[3]) : 0.0));