Re: Graph library connected_components usage Q1

From: Rob Smallshire (robert_at_[hidden])
Date: 2001-07-25 04:21:26

Hi Jeremy,

> > Q1:
> >
> > Compiling the following two lines:
> >
> > std::vector<int> component(boost::num_vertices(G));
> > int num = boost::connected_components(G, &component[0]);
> 
> Could you show my what type G is. A small compilable program example
> demonstrating the problem would be best.

Here you are - this program gives an identical error on MSVC6.0sp5,

C:/users/rob/dev/utils/boost/boost_1_22_0\boost/property_map.hpp
(185) : error C2664: 'void __cdecl boost::put(int *,int,
const int &)' : cannot convert parameter 2 from 'void *' to 'int'
This conversion requires a reinterpret_cast, a C-style cast or 
function-style cast C:/users/rob/dev/utils/boost/boost_1_22_0
\boost/property_map.hpp(183) : while compiling class-template member 
function 'void __thiscall boost::WritablePropertyMapConcept<int 
*,void *>::constraints(void)'

Program :

#include <iostream>
#include <vector>
#include <boost/smart_ptr.hpp>
#include <boost/property_map.hpp>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/connected_components.hpp>

class baseT
{
   // In my full code baseT is a class template parameter and
   // everything else below is wrapped up in a class
};

typedef unsigned int setID;

struct object_t
{
   enum { num = 4562 }; /*< Unique id for this tag */
   typedef boost::vertex_property_tag kind;
};

struct set_t
{
   enum { num = 4563 }; /*< Unique id for this tag */
   typedef boost::vertex_property_tag kind;
};

struct component_t
{
   enum { num = 4564 };
   typedef boost::vertex_property_tag kind;
};

typedef boost::property<object_t, const baseT *> VertexObjectProperty;
typedef boost::property<set_t, setID, VertexObjectProperty> 
VertexSetProperty;
typedef boost::property<component_t, int, VertexSetProperty> 
VertexComponentProperty;

typedef boost::property<boost::edge_weight_t, int> EdgeWeightProperty;

typedef boost::adjacency_list<boost::listS, boost::setS, 
boost::undirectedS, VertexSetProperty ,EdgeWeightProperty> Graph;
        
typedef boost::property_map<Graph, component_t>::type 
ComponentPropertyMap;

int main(int argc, char* argv[])
{
   Graph G;

   std::vector<int> component(boost::num_vertices(G));
   int num = boost::connected_components(G, &component[0]);

   return 0;
}