[multi_index] Sorting object based on some specified criteria !!
Hi all, I have following kind of class and having some identifier and group id associated with particular procedure. I want to know if I have to get the procedures relating particular group for ex. (groupId == 1). How do I do using multiindex container? Can somebody please give me some hint or code if they have done something similar to what I want to do? Thanks a lot, Priyank // class procedure test class Procedure { public: Procedure(int _id, int _group ) : id_(_id), group_(_group) { } int get_id() const { return id_; } int get_group() const { return group_; } friend ostream& operator << (ostream& _os, const Procedure& _proc); private: int id_; int group_; }; ostream& operator << (ostream& _os, const Procedure& _proc) { _os << "PROCEDURE : " << _proc.id_ << endl; return _os; } // Defines multiindex container that is hashed based on id struct id { }; typedef multi_index_container< Procedure*, indexed_by< hashed_unique< tag<id>, const_mem_fun<Procedure, int, &Procedure::get_id> >
Procedure_Hashed_Pool;
typedef Procedure_Hashed_Pool::index<id>::type Procedure_By_Id;
Patel Priyank-PPATEL1 <priyankpatel <at> motorola.com> writes:
Hi all,
I have following kind of class and having some identifier and group id associated with particular procedure. I want to know if I have to get the procedures relating particular
group for ex. (groupId == 1). How do I do using multiindex container? Can somebody please give me some hint or code if they have done something similar to what I want to do?
Hello Priyank, I'm not sure I've understood what you're after, but let me try anyway: As you'll search for group, you'll need an additional index (the one you've set up is based on process ID). The following has not been compiled, beware typos: struct id {}; struct group {}; typedef multi_index_container< Procedure*, indexed_by< hashed_unique< tag<id>, const_mem_fun<Procedure, int, &Procedure::get_id> > >, hashed_non_unique< tag<group>, const_mem_fun<Procedure, int, &Procedure::get_group> > > >
Procedure_Hashed_Pool; typedef Procedure_Hashed_Pool:: index<id>::type Procedure_By_Id; typedef Procedure_Hashed_Pool:: index<group>::type Procedure_By_Group; (I've decided to make the new index hashed non-unique, you could also have it ordered non-unique if you need the elements to be sorted by group ID --hashing only guarantees fast retrieval.) And now you can simply use equal_range() on this index to do what you want: int gr=...; const Procedure_By_Group& procedure_bg= procedure_pool.get<group>(); std::pair< Procedure_By_Group::iterator, Procedure_By_Group::iterator
p=procedure_bg.equal_range(gr);
p will hold the range of elements with group ID == gr. Is this what you were after? Joaquín M López Muñoz Telefónica, Investigación y Desarrollo
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Joaquin M Lopez Munoz -
Patel Priyank-PPATEL1