Question

I have a class with a struct in it and a list with these structs.
But when I iterate through this list I can’t get the properties out of my struct.

error: request for member ‘x_’ in ‘it.std::_List_const_iterator<_Tp>::operator* with _Tp = AStarPlanner::Cell*’, which is of non-class type ‘AStarPlanner::Cell* const’

Header file:

class AStarPlanner {

public:

  AStarPlanner(int width, int height, const costmap_2d::Costmap2D* costmap);

  virtual ~AStarPlanner();


 protected:

  struct Cell {

        int x_;
        int y_;
        int f_;   // f = g + h
        int g_;   // g = cost so far
        int h_;   // h = predicted extra cost

        //CellInfo* visited_from_; // pointer to cell from which this cell is visited

        Cell(int x, int y, int g, int h) : x_(x), y_(y), g_(g), h_(h) {
                f_ = g_ + h_;
        }
    };

    bool cellInList(const Cell* cell, const std::list<Cell*> liste);

    };

cpp file:

bool AStarPlanner::cellInList(const Cell* cell, const list<Cell*> liste)
{
  list<Cell*>::const_iterator it;
  for (it = liste.begin(); it != liste.end(); it++)
  {
     if ( it->x_ == cell->x_ && it->y_ == cell->y_)
        return true;
  }

  return false;
 }

Answer 1

You have a list<Cell*>, so you need to dereference the iterator and the pointer.

for (it = liste.begin(); it != liste.end(); it++)
{
   if ( (*it)->x_ == cell->x_ && (*it)->y_ == cell->y_)
      return true;
}