title: Creating and filling a ROOT file from a text file
body: <p>this is about C++ coding in CERN ROOT.
  So I have a text file with columns of data. Now I need to make a .root file with all the data in a tree. How would I do this? Also, if the text file has column headers, how would I write my code to get them to be my tree's branch names?
  Thanks in advance!</p>