TListAndSTL.C File Reference

This is an example of using TList with STL algoritms in CINT. More...

Go to the source code of this file.

Detailed Description

This is an example of using TList with STL algoritms in CINT.

Output produced by .x TListAndSTL.C

Processing /mnt/vdb/lsf/workspace/root-makedoc/rootspi/rdoc/src/master/tutorials/cont/TListAndSTL.C...
Value: test string #0
Value: test string #1
Value: test string #2
Value: test string #3
Value: test string #4
Value: test string #5
Value: test string #6
Value: test string #7
Value: test string #8
Value: test string #9
The string has been found: test string #4

TListAndSTL.C code

// STD
#include <algorithm>
#include <iostream>
#include <sstream>

// ROOT
#include "TList.h"
#include "TCollection.h"
#include "TObjString.h"

// A functor for the for_each algorithm
struct SEnumFunctor {
   bool operator()(TObject *aObj) {
      if (!aObj)
         return false;

      TObjString *str(dynamic_cast<TObjString*>(aObj));
      if (!str)
         return false;

      cout << "Value: " << str->String().Data() << endl;
      return true;
   }
};

// A functor for the find_if algorithm
struct SFind {
   // using this ugly constructor, since there is problems with std::bindX in CINT
#ifdef __CINT__
   SFind(const SFind &oth) : fToFind(oth.fToFind) {}
   SFind(const TString aStr): fToFind(aStr) {
#else
   SFind(const TString &aStr): fToFind(aStr) {
#endif
   }
   bool operator()(TObject *aObj) {
      TObjString *str(dynamic_cast<TObjString*>(aObj));
      return !str->String().CompareTo(fToFind);
   }
private:
   const TString fToFind;
};


// The "main" function
void TListAndSTL()
{
   const Int_t size(10);

   // Initializing TList container
   TList list;
   ostringstream ss;
   for (int i = 0; i < size; ++i) {
      ss << "test string #" << i;
      TObjString *s(new TObjString(ss.str().c_str()));
      list.Add(s);
      ss.str("");
   }


   //->>>>>>> Example #1 <<<<<<<-
   // running the std::for_each algorithm on the list
   TIter iter(&list);
   for_each(iter.Begin(), TIter::End(), SEnumFunctor());

   //->>>>>>> Example #2 <<<<<<<-
   // we can try to find something in the container
   // using the std::find_if algorithm on the list
   string strToFind("test string #4");
   SFind func(strToFind.c_str());


#ifdef __CINT__
   TIter found(
      find_if(iter.Begin(), TIter::End(), func)
   );
#else // in compilation mode you need to use TIterCategory as an iterator for such a algorithm like find_if
   TIterCategory<TList> iter_cat(&list);
      TIterCategory<TList> found(
         find_if(iter_cat.Begin(), TIterCategory<TList>::End(), func)
      );
#endif

   // Checking the result
   if (!(*found)) {
      cerr << "Can't find the string: \"" << strToFind << "\" in the container" << endl;
      return;
   }

   TObjString *str(dynamic_cast<TObjString*>(*found));
   if (!str) {
      cerr << "Can't find the string: \"" << strToFind << "\" in the container" << endl;
      return;
   }

   cout << "The string has been found: " << str->String().Data() << endl;
}

Author

Anar Manafov

Definition in file TListAndSTL.C.