.i means ignore, use for comments
.i H. Schellman - Aug 16, 2000 - based on Florencia Canelli's example

.i open a file

TFile *emroot = TFile::Open("/prj_root/802/alg_18/root/hms-zee-example.root","READ");

.i make a browser;

TBrowser b;         

.i look in the browser and click on your root file to see name of 'root-tuple' it is Global;

.i tell root what tree you want

tree = (TTree*)gDirectory->Get("Global")

.i now to do some analysis

.i Global->MakeClass("emstudy");  makes a new class

.i Here we use a pre-existing example 
.i load the analysis class I made earlier using Global->MakeClas

.L emstudy.C

.i make an instance of the analysis class and point it at the tree from your new file - will default to the file class was made with.
     
emstudy ex(tree);      

.i loop over the events

ex.Loop();
      
.i show the contents of event 1

ex.Show(1);     

.i draw a histogram

h_eemass->Draw();