"Warning : illegal numerical expression"?

Hello ROOTers,

I’m a newcomer both to ROOT and C++, so forgive me if the following question is stupid.

I need to fill a TH2F with data from a 2D table and plot it along with the result of some calculations. I use the following code :

in a loop to fill up the histogram, and
to plot it.
PDF2D[k][l] is of type Float_t.

I get the following error messages, that I don’t understand.

Warning: Illegal numerical expression 2Dfit->SetCellContent(k,l,PDF2D[k][l]) Warning: Illegal numerical expression 2Dfit->SetLineColor(2) Warning: Illegal numerical expression 2Dfit->Draw("SAME")

I’m using ROOT 3.04/02, but upgrading is not an option as it’s not locally installed on my machine.



variable names cannot start with a digit in C++.

Thanks a lot!