Hi,
I am facing compilation error in the following code. I do understand why
the error is, but I could not find a good solution. Here is my code and
question explained in detail
*What I want to do:* I want to store a key- value pair where both key and
its respective values is unique. But After I create a map, I want to use
the VALUE and get the corresponding key. Essentially the best way is a
bimap. So I do the following using associative property maps.
*What I did:*
1. define a bimap (my_bimap )
2. define associative property map for left view of bimap (
right_asso_bimap )
3. define associative property map for right view of bimap (
left_asso_bimap )
4. fill the bimap using *left* view associative property map.
i.e. *use boost::put( left_asso_bimap, key, value )*
5. Now using *right* view associative property map, retrieve key for given
value
i.e. use *boost::get( right_asso_bimap, value )*
My main motive is to use GET and PUT helper functions for insertion and
retrieval from a bimap. Use PUT to insert in LEFT BIMAP. and Use GET to
retrieve from RIGHT BIMAP.
I know the error is because of non-const-ness of the iterators because of
which I cannot de-reference using iterators. But what would be the
alternative to this ?
This link here explains how to define parameters for bimap in order for
iterators to be mutable.
http://www.boost.org/doc/libs/1_55_0/libs/bimap/doc/html/boost_bimap/the_tut...
*But I get the error below: *
In file included from main.cpp:2:0:
/usr/local/include/boost/property_map/property_map.hpp: In
instantiation of
'boost::associative_property_map<UniquePairAssociativeContainer>::value_type&
boost::associative_property_map<UniquePairAssociativeContainer>::operator[](const
key_type&) const [with UniquePairAssociativeContainer =
boost::bimaps::views::list_map_view >
boost::associative_property_map<UniquePairAssociativeContainer>::reference
= const int&; boost::associative_property_map<UniquePairAssociativeContainer>::value_type
= const int; boost::associative_property_map<UniquePairAssociativeContainer>::key_type
= long unsigned int]':
/usr/local/include/boost/property_map/property_map.hpp:357:54:
required from 'Reference boost::get(const
boost::put_get_helper&, const K&) [with
PropertyMap = boost::associative_property_map > > Reference = const
int&; K = int]'
main.cpp:41:35: required from here
/usr/local/include/boost/property_map/property_map.hpp:502:20: error:
no match for 'operator[]' (operand types are
'boost::associative_property_map > >::C {aka
boost::bimaps::views::list_map_view >}' and 'const key_type
{aka const long unsigned int}')*
*return (*m_c)[k];*
^
Here my code. You can also see the code here on this website link:*
http://coliru.stacked-crooked.com/a/59cbf2c564bf22b2
http://coliru.stacked-crooked.com/a/59cbf2c564bf22b2*
#include #include
#include
#include
#include <iostream>
using namespace boost;
int main() {typedef int vertex_descriptor_t;namespace bm =
boost::bimaps;typedef bm::bimap< vertex_descriptor_t,
bm::list_of > vd_idx_bimap_t;typedef
boost::associative_property_map
Lasso_vd_idx_bimap_t;typedef
boost::associative_property_map
Rasso_vd_idx_bimap_t;
// define bimap and assoc prop map for itvd_idx_bimap_t
my_bimap;Lasso_vd_idx_bimap_t Lmy_asso_bimap(my_bimap.left
);Rasso_vd_idx_bimap_t Rmy_asso_bimap(my_bimap.right);
typedef typename vd_idx_bimap_t::value_type value_type;
my_bimap.insert( value_type( 1, 100 ) );
my_bimap.insert( value_type( 2, 200 ) );
int z = 1;
std::cout << "value = " << get ( my_bimap.left, z ) << std::endl;
// prints correctly value = 100
// use left asso bimap for inserting to bimap
boost::put( Lmy_asso_bimap, 3, 300 ); // correct
// print bimap using *left view*for(auto t = my_bimap.left.begin(); t
!= my_bimap.left.end(); ++t)
std::cout << t->first << " " << t->second << "\n";
int y = 2;*z **= boost::get( Lmy_asso_bimap, y ); // CORRECT OUTPUT
for left view *
std::cout << "value = " << z << std::endl;
// Use right asso bimap to get key based on supplied value
y = 100;*z = boost::get( Rmy_asso_bimap, y );* *// -->> ERROR HERE
for right view*
std::cout << "value = " << z << std::endl;
// print map again. (*right view*)for(auto t = my_bimap.right.begin();
t != my_bimap.right.end(); ++t)
std::cout << t->first << " " << t->second << "\n";
}
Please let me know whether this is a potential bug, or the code semantics
is incorrect. Or the current library cannot support this. ?
Regards,
Aniket Pugaonkar
--
Thanks and regards,
Aniket Pugaonkar
