Create mutliple histogram objects

[dhsmith]

Hi,

Yes it’s possible. In fact there are quite a lot of ways to do this; you could have a look through previous postings. For instance:

Vector(stl) of TH1F* objects

Hello! This is my first post. I don’t know much about C++. Well, I have a problem with vectors of TH1F* objects. I would like to know if it’s possible and how to store in a vector a number of histograms, each one with a different identificator. For example, vector a; for(int i=0;i<100;i++){ TH1F *a= new TH1F(...); v.push_back(a); } But, in this case all the vectors hace the same identificator. Also, in this case I have memory leaks. Also, is another possibility to make that thing? Tlist…

In your example the error quoted is because variable length arrays aren’t allowed (although there are some other problems in the example).

One possibility could be to use a vector of pointers to TH1F objects:

#include <vector>

std::vector<TH1F*> test_root(Int_t number, const char *name, Int_t nbins, Double_t bin_low, Double_t bin_high){
  std::vector<TH1F*> v;
  for(Int_t i=1;i<=number;i++) {
    TString hname = TString::Format("h%s%d",name,i);
    TH1F *h = new TH1F(hname.Data(),"",nbins,bin_low,bin_high);
    v.push_back(h);
  }
  return v;
}