using transform_iterator with std::lower_bound

5 Feb 2008

      Hi,

I'm trying to use a transform iterator and lower_bound
to search a list of integers as if it was list of
booleans.  

According to the message the const_mem_fun_ref_t
doesn't have a default constructor. Is there a way to
make this code compile?  

Your help will be appreciated!
Alex

#include<functional>
#include <vector>
#include <algorithm>
#include 

class T
{
public:
	int _a;
	T(int a) : _a(a) {}
	bool greaterZero() const { return _a > 0; }
};

int main(void)
{
	typedef std::vector<T> Tlist;
	typedef std::const_mem_fun_ref_t Function;
    typedef boost::transform_iterator Iterator;

	Tlist x;
	Iterator
b(x.begin(),std::mem_fun_ref(&T::greaterZero)),

e(x.end(),std::mem_fun_ref(&T::greaterZero));

	std::lower_bound(b,e,false);   
}

Error log:
BD Software STL Message Decryptor v3.10 for gcc 2/3/4
matob.cpp:28:2: warning: no newline at end of file
/cygdrive/c/opt/boost_1_34_1/boost/iterator/transform_iterator.hpp:
In
    constructor 
   `boost::transform_iterator<
        main()::Function, vector<T>::const_iterator,
boost::use_default
      , boost::use_default
    >::transform_iterator()':
stl_algo.h:2627:   instantiated from 
   `boost::transform_iterator<
        main()::Function, vector<T>::const_iterator,
boost::use_default
      , boost::use_default
    > lower_bound(
        boost::transform_iterator<
            main()::Function,
vector<T>::const_iterator, boost::use_default
          , boost::use_default
        >, boost::transform_iterator<
            main()::Function,
vector<T>::const_iterator, boost::use_default
          , boost::use_default
        >, const bool &
    )'
matob.cpp:26:   instantiated from here
/cygdrive/c/opt/boost_1_34_1/boost/iterator/transform_iterator.hpp:100:
error:
    No match for `const_mem_fun_ref_t::const_mem_fun_ref_t()'
stl_function.h:640: candidates are:
const_mem_fun_ref_t
    ::const_mem_fun_ref_t(const
const_mem_fun_ref_t &)
stl_function.h:644:  const_mem_fun_ref_t<
        bool, T>::const_mem_fun_ref_t(bool (T::*)()
const)

Programming Tutorial:
In Python: To do this, do this
In Perl: To do this, do this or this or this or this...
In C: To do this, do this, but be careful
In C++: To do this, do this, but don't do this, be careful of this, watch out for this, and whatever you do, don't do this

      ____________________________________________________________________________________
Never miss a thing.  Make Yahoo your home page. 
http://www.yahoo.com/r/hs

Alexis H. Rivera-Rios

chun ping wang

chun ping wang

tags

participants (2)