Question

I’ve question to ask.

I’ve created a class called AstarPlanlama and have these 2 functions:

bool AstarPlanlama::nodeComp(const Node* lhs, const Node* rhs) 
{
   return lhs->F < rhs->F;
}

void AstarPlanlama::enKucukFliNodeBul(std::list<Node*> * OPEN)
{
    std::list<Node*>::iterator it = std::min_element(OPEN->begin(), OPEN->end(), &AstarPlanlama::nodeComp);

    OPEN->sort(&AstarPlanlama::nodeComp);   

    Q = OPEN->front();      

    OPEN->pop_front();      
}

When I compile my code the error occurs in the xutility.h file.

template<class _Pr, class _Ty1, class _Ty2> inline
    bool _Debug_lt_pred(_Pr _Pred,
        _Ty1& _Left, _Ty2& _Right,
        _Dbfile_t _File, _Dbline_t _Line)
    {   // test if _Pred(_Left, _Right) and _Pred is strict weak ordering
    if (!_Pred(_Left, _Right))
        return (false);
    else if (_Pred(_Right, _Left))
        _DEBUG_ERROR2("invalid operator<", _File, _Line);
    return (true);
    }

Declerations of the functions:

    bool nodeComp(const Node* lhs, const Node* rhs);

    void enKucukFliNodeBul(std::list<Node*> * OPEN);

The error line is if (!_Pred(_Left, _Right))

What is wrong with the code?

Thank you for your returns..

My regards..

Answer 1

It looks like you are passing a member function as your custom comparator.
Make it static or use std::bind:

 std::list<Node*>::iterator it = std::min_element(OPEN->begin(), OPEN->end(),
                                       std::bind(&AstarPlanlama::nodeComp, 
                                                 this,
                                                 std::placeholders::_1,
                                                 std::placeholders::_2));

OPEN->sort(std::bind(&AstarPlanlama::nodeComp, 
                     this,
                     std::placeholders::_1,
                     std::placeholders::_2));

Member functions are special and need to be called on an object, this is why std::bind is needed to bind to the this pointer.