How to merge two histograms into one

ROOT
1

Hi, all
I am a beginner, now I encounter an “easy” problem, I don’t know which dirrective I can use when I what to merge two histograms into one. Just reading them , then use h1->Draw(“same”) ?
Any help will be appreciated!

Thank you!

Xuebing

2

Use TH1::Add, eg

    TH1 *h1, *h2;
    h1->Add(h2);

see also TH1::Merge to merge a list of histograms
and $ROOTSYS/bin/hadd to merge a list of ROOT files

Rene

3

Hi brun,
I used your response to merge two histograms plots into single plot. When i typed these commands i got an error(see screenshot).
Any kind of help will meant me alot!!
Screenshot from 2020-07-27 23-17-01|690x387

4

The code in @brun post was just showing the “idea”.
The following is real C++:

auto h1 = new TH1F();
auto h2 = new TH1F();
h1->Add(h2);

of course it is a bit useless as h1 and h2 are empty.