[Boost-users] Question on ptr_vector class

From: Sebastien Fortier (sebastien.fortier_at_[hidden])
Date: 2006-03-21 07:39:21

I would like to define two different sorting predicates for a class
but I do not understand how to do this.

//meteorlogicalObj.hpp
class meteorlogicalObj {
public:
   meteorlogicalObj(int val, Point pt)    : val_(val), pt_(pt){}
   virtual      ~meteorlogicalObj() {}

   // how would I go about creating these sorting functions that would 
work with the ptr_vector class
   bool sortOnValue(const meteorlogicalObj&, const meteorlogicalObj&);
   bool sortOnPoint(const meteorlogicalObj&, const meteorlogicalObj&);
   // ...
private:
   int val_;
   Point pt_;
};

//meteorlogicalObj.cpp
#include "meteorlogicalObj.h"

bool meteorlogicalObj::sortOnValue(const meteorlogicalObj& metObj, const 
meteorlogicalObj& other)
{
   return (metObj.val_ < other.val_);
}

bool meteorlogicalObj::sortOnPoint(const meteorlogicalObj& metObj, const 
meteorlogicalObj& other)
{
   return (metObj.pt_ < other.pt_);
}

//main.cpp
boost::ptr_vector<meteorlogicalObj>  metObjVec;

//... fill vector

metObjVec.sort( sortOnValue() ); // this does not work, what is missing???
metObjVec.sort( sortOnPoint() ); // this does not work, what is missing???

I can see that I probably need the indect_fun but I do not know how to 
wrap my sorting function to pass them to the sorting function

Thank you for your assistance!