// Read the previously produced N-Tuple and print on screen
// its content

void read_ntuple_from_file(){

    // Open a file, save the ntuple and close the file
    TFile in_file("conductivity_experiment.root");
    TNtuple* my_tuple = (TNtuple*) in_file.GetObjectChecked(
                                   "cond_data",
                                   "TNtuple");
    float pot,cur,temp,pres; float* row_content;

    cout << "Potential\tCurrent\tTemperature\tPressure\n";
    for (int irow=0;irow<my_tuple->GetEntries();++irow){
        my_tuple->GetEntry(irow);
        row_content = my_tuple->GetArgs();
        pot = row_content[0];
        cur = row_content[1];
        temp = row_content[2];
        pres = row_content[3];
        cout << pot << "\t" << cur << "\t" << temp 
             << "\t" << pres << endl;
        }

    }