Passing a function_pointer as a comparator in a stl make_heap c++ -

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i'm developing program run dijkstra's algorithm heap implementation , want versatile can i'm using function pointer in order avoid code repetition. error pops. i'm using stl make_heap

"type must use '.*' or '->*' call pointer-to-member function in '__comp (...)', e.g. '(... ->* __comp) (...)' "heap.h     c/c++ problem

here dijkstra's algorithm:

void graph::dijkstraalg(vertex* ini, vertex* fin, void(graph::*weight_filler)(void), bool(graph::*pq_order)(const vertex* &, const vertex* &)){  for(unsigned int = 0; < vertexs.size(); i++) {     vertexs[i]->path = null;     vertexs[i]->holder = max_int_value;     vertexs[i]->processing=false; }  (this->*weight_filler)();  vertex* v=ini; v->holder = 0; v->processing = true;  vector<vertex*> pq; pq.push_back(v); make_heap(pq.begin(),pq.end(),pq_order);  while(!pq.empty()){      v=pq.front();     pop_heap(pq.begin(),pq.end());     pq.pop_back();      for(unsigned int u=0; u < v->adj.size(); u++){          vertex* w = v->adj[u]->dest;          if((v->holder+v->adj[u]->weight) < w->holder){              w->holder=v->holder + v->adj[u]->weight;             w->path=v;              if(!w->processing){                  w->processing=true;                 pq.push_back(w);             }         }          make_heap(pq.begin(),pq.end(),pq_order);     } }  return;}

the error in make_heap , can't figure out, appreciated.

here function i'm passing make_heap:

bool graph::regular_pqorder(const vertex* &v, const vertex* &u){ return v->holder > u->holder;}

this how call algo:

dijkstraalg(i,f,&graph::price_weightfiller,&graph::regular_pqorder);

if need more information tell me , edit it. thank pal's

i have simplified problem to:

#include <algorithm> #include <vector>  using namespace std;  class vertex {};  class graph { public:     void dijkstraalg(vertex* ini, vertex* fin, void(graph::*weight_filler)(void),                                                 bool(graph::*pq_order)(const vertex*, const vertex*))     {         (this->*weight_filler)();          struct comparator         {         private:              graph* m_g;             bool(graph::*m_fn)(const vertex*, const vertex*);         public:             comparator(graph* g, bool(graph::*fn)(const vertex*, const vertex*)) : m_g(g), m_fn(fn)             {}              bool operator()(const vertex* one, const vertex* two) const             {                 return (m_g->*m_fn)(one, two);             }         };          comparator comparator(this, pq_order);          vector<vertex*> pq;         std::make_heap(pq.begin(), pq.end(), comparator);     }      void weight_filler1()     {             }     bool pq_order1(const vertex*, const vertex*)     {         return false;     }  };  int main() {     graph g;     g.dijkstraalg(nullptr, nullptr, &graph::weight_filler1, &graph::pq_order1);      return 0; }

the problem is: std::make_heap expects function pointer- in case passing pointer member function issue.

either can change declaration of dijkstraalg take in static function pointer pq_order or wrap pq_order in structure make callable entity in have done.

note: have fixup references pointers in pq_order make_heap compile anyway


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