tree500_cernbuild.C File Reference

Detailed Description

Read data (CERN staff) from an ascii file and create a root file with a Tree.

 
TFile *tree500_cernbuild(Int_t getFile = 0, Int_t print = 1)
{
   Int_t  Category;
   UInt_t Flag;
   Int_t  Age;
   Int_t  Service;
   Int_t  Children;
   Int_t  Grade;
   Int_t  Step;
   Int_t  Hrweek;
   Int_t  Cost;
   Char_t Division[4];
   Char_t Nation[3];
 
   // The input file cern.dat is a copy of the CERN staff data base from 1988
   TString filename = "cernstaff.root";
   TString dir = gROOT->GetTutorialDir();
   dir.Append("/io/tree/");
   dir.ReplaceAll("/./","/");
   FILE *fp = fopen(Form("%scernstaff.dat", dir.Data()), "r");
 
   TFile *hfile = 0;
   if (getFile) {
      // if the argument getFile =1 return the file "cernstaff.root"
      // if the file does not exist, it is created
      if (!gSystem->AccessPathName(dir + "cernstaff.root", kFileExists)) {
         hfile = TFile::Open(dir + "cernstaff.root"); //in $ROOTSYS/tutorials/io/tree
         if (hfile)
            return hfile;
      }
      // otherwise try $PWD/cernstaff.root
      if (!gSystem->AccessPathName("cernstaff.root", kFileExists)) {
         hfile = TFile::Open("cernstaff.root"); //in current dir
         if (hfile)
            return hfile;
      }
   }
   //no cernstaff.root file found. Must generate it !
   //generate cernstaff.root in $ROOTSYS/tutorials/io/tree if we have write access
   if (gSystem->AccessPathName(".", kWritePermission)) {
      printf("you must run the script in a directory with write access\n");
      return 0;
   }
   hfile = TFile::Open(filename, "RECREATE");
   auto tree = new TTree("T", "CERN 1988 staff data");
   tree->Branch("Category", &Category, "Category/I");
   tree->Branch("Flag", &Flag, "Flag/i");
   tree->Branch("Age", &Age, "Age/I");
   tree->Branch("Service", &Service, "Service/I");
   tree->Branch("Children", &Children, "Children/I");
   tree->Branch("Grade", &Grade, "Grade/I");
   tree->Branch("Step", &Step, "Step/I");
   tree->Branch("Hrweek", &Hrweek, "Hrweek/I");
   tree->Branch("Cost", &Cost, "Cost/I");
   tree->Branch("Division", Division, "Division/C");
   tree->Branch("Nation", Nation, "Nation/C");
   char line[80];
   while (fgets(line, 80, fp)) {
      sscanf(&line[0],"%d %d %d %d %d %d %d  %d %d %s %s",
      &Category, &Flag, &Age, &Service, &Children, &Grade, &Step, &Hrweek, &Cost, Division, Nation);
      tree->Fill();
   }
   if (print)
      tree->Print();
   tree->Write();
 
   fclose(fp);
   delete hfile;
   if (getFile) {
      //we come here when the script is executed outside $ROOTSYS/tutorials/io/tree
      hfile = TFile::Open(filename);
      return hfile;
   }
   return 0;
}

 
******************************************************************************
*Tree    :T         : CERN 1988 staff data                                   *
*Entries :     3354 : Total =          176339 bytes  File  Size =      15005 *
*        :          : Tree compression factor =   2.74                       *
******************************************************************************
*Br    0 :Category  : Category/I                                             *
*Entries :     3354 : Total  Size=      14073 bytes  One basket in memory    *
*Baskets :        0 : Basket Size=      32000 bytes  Compression=   1.00     *
*............................................................................*
*Br    1 :Flag      : Flag/i                                                 *
*Entries :     3354 : Total  Size=      14049 bytes  One basket in memory    *
*Baskets :        0 : Basket Size=      32000 bytes  Compression=   1.00     *
*............................................................................*
*Br    2 :Age       : Age/I                                                  *
*Entries :     3354 : Total  Size=      14043 bytes  One basket in memory    *
*Baskets :        0 : Basket Size=      32000 bytes  Compression=   1.00     *
*............................................................................*
*Br    3 :Service   : Service/I                                              *
*Entries :     3354 : Total  Size=      14067 bytes  One basket in memory    *
*Baskets :        0 : Basket Size=      32000 bytes  Compression=   1.00     *
*............................................................................*
*Br    4 :Children  : Children/I                                             *
*Entries :     3354 : Total  Size=      14073 bytes  One basket in memory    *
*Baskets :        0 : Basket Size=      32000 bytes  Compression=   1.00     *
*............................................................................*
*Br    5 :Grade     : Grade/I                                                *
*Entries :     3354 : Total  Size=      14055 bytes  One basket in memory    *
*Baskets :        0 : Basket Size=      32000 bytes  Compression=   1.00     *
*............................................................................*
*Br    6 :Step      : Step/I                                                 *
*Entries :     3354 : Total  Size=      14049 bytes  One basket in memory    *
*Baskets :        0 : Basket Size=      32000 bytes  Compression=   1.00     *
*............................................................................*
*Br    7 :Hrweek    : Hrweek/I                                               *
*Entries :     3354 : Total  Size=      14061 bytes  One basket in memory    *
*Baskets :        0 : Basket Size=      32000 bytes  Compression=   1.00     *
*............................................................................*
*Br    8 :Cost      : Cost/I                                                 *
*Entries :     3354 : Total  Size=      14049 bytes  One basket in memory    *
*Baskets :        0 : Basket Size=      32000 bytes  Compression=   1.00     *
*............................................................................*
*Br    9 :Division  : Division/C                                             *
*Entries :     3354 : Total  Size=      25326 bytes  File Size  =       8325 *
*Baskets :        1 : Basket Size=      32000 bytes  Compression=   2.49     *
*............................................................................*
*Br   10 :Nation    : Nation/C                                               *
*Entries :     3354 : Total  Size=      24209 bytes  File Size  =       6680 *
*Baskets :        1 : Basket Size=      32000 bytes  Compression=   3.05     *
*............................................................................*
(TFile *) nullptr

Author

Rene Brun

Definition in file tree500_cernbuild.C.