在C ++中的向量中使用指针后出现段错误

Question

i am running into a segfault in my c++ program and can't figure out my mistake.
I have a class Map which is a 2D-vector of objects of the class MapCells. The task is to go from cell to cell. From each cell, there are two possible ways to other cells. Maybe some 'pseudo' code can explain it better:

//map.h

class MapCell {
private:
    MapCell *p_way1_, *p_way2_;
    int some_information_;

public:
    MapCell* getWayPointer1();
    MapCell* getWayPointer2();
    int getInformation();

    void setWayPointer1(MapCell* new_p_way1);
    void setWayPointer1(MapCell* new_p_way2);
};

class Map {
private:
    std::vector< std::vector<MapCell> > map_;
public:
    void initializeMap();
    MapCell* getStartPointer();
};

int main()
{
    Map map;
    map.initializeMap();

    MapCell *p_current_cell, *p_next_cell;
    p_current_cell = map.getStartPointer();

    while(p_current_cell->getInformation() != 0)
    {
        if(p_current_cell->getInformation() == 1)
        {
            p_next_cell = p_current_cell->getWayPointer1();
        }
        else
        {
            p_next_cell = p_current_cell->getWayPointer2();
        }

        p_current_cell = p_next_cell;
    }

    return 0;
}

This is only a little part of the real code. But i think i made a fundamental mistake so i hope this is enough code to fix it. The problem is, that my code runs for minutes without problems and suddenly i get a segfault. gdb states, that the segfault happens when getInformation() is called. I also found out, that at some point all p_way2_ vectors lead to nonsense. Can you help me?

Thank you very much in advance!

Answer 1

Problem in lines

MapCell* p_current_cell, p_next_cell;

MapCell* p_way1_, p_way2;

Second parameter is not pointer and MapCell is implicit convert from pointers (or you will get multiple compile-times errors). Try change to

MapCell* p_current_cell, *p_next_cell;

MapCell* p_way1_, *p_way2;