On Fri, 31 Jan 2003, Arthur E. Snyder wrote:
>Maybe you could use an stl vector instead?
I can, but then I need to call the push_back method every time I add an
element. As the size of the array is constant and known, I want to
allocate memory only once (and eventually re-use it for the next event)
Carlos
>
>#include <vector>
>
>//declare
>std::vector<Float_t> array;
>
>//add next element
>array.push_back(aFloat);
>
>Int_t size=array.size();
>
>stl vectors should at least work in compiled code. I'm not sure if they're
>implemented in intrepreter.
>
>
>
>
>
>
>A.E. Snyder, Group EC \!c*p?/
>SLAC Mail Stop #95 ((. .))
>Box 4349 |
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>FAX:650-926-2657 Collaboration
>
>
>
>On Fri, 31 Jan 2003, Carlos Muņoz Camacho wrote:
>
>>
>> Hi,
>>
>> I have a class similar to Event.h with an array of Float_t as a member.
>> I want the dimension of the array to be a non-const parameter (as it will
>> be read from an input file). The parameter is a static member of an
>> inherited class, but this can change. The important thing is I don't want
>> to hardcode the value of the parameter, because it is read from a file.
>>
>> The solution I found in the documentation is to allocate it dynamically
>> via a pointer and tell the streamer the size of the array in the
>> commentary field : //[fSize] . However, fSize needs to be a data member of
>> the class. Obviously, I don't want to save this data member to file
>> because it is constant for all the events. If I use fSize //! to avoid
>> writing it, I get an Error in <TStreamerInfo::Build>. Below is a short
>> example which reproduces the problem.
>>
>> Is there a way around this?
>>
>> ROOT 3.03/08 on a RH 7.2
>>
>>
>> File: class.C
>> ______________________________________________________
>>
>> #include "TObject.h"
>>
>> class TEvent : public TObject {
>>
>> private :
>>
>> Int_t fSize; //!
>> Float_t* fBlocks; //[fSize]
>>
>> ClassDef(TEvent,1)
>>
>> };
>> _______________________________________________
>>
>> Result:
>>
>> CINT/ROOT C/C++ Interpreter version 5.15.53, Aug 15 2002
>> Type ? for help. Commands must be C++ statements.
>> Enclose multiple statements between { }.
>> root [0] .L class.C+
>> Info in <TUnixSystem::ACLiC>: creating shared library
>> /dsm/phnpcd232/local/home/cmunoz/./class_C.so
>> root [1] TEvent *ev=new TEvent();
>> root [2] TTree t("t","My tree");
>> root [3] t.Branch("event","TEvent",&ev,16000,99);
>> Error in <TStreamerInfo::Build>: TEvent, discarding: Float_t* fBlocks,
>> illegal [fSize]
>>
>>
>>
>> Carlos Munoz Camacho
>> SPhN/CEA-Saclay
>>
>>
>
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