Segmentation Fault Problem

[martianxx]

I have a pointer to a Level class and when I change level I want to delete that pointer (to free the memory) and construct a new Level with the same pointer curLevel_ = new Level(string)

However when I do this I get a segmentation fault. Here is my code:

//system_state.cpp
SystemState::SystemState()
{
    curLevel_ = new Level(std::string("resources/files/level1.txt"));
}
void SystemState::onUpdate()
{
    if (curLevel_ != 0)
        curLevel_->Update();
}
void SystemState::onRender( Canvas& canvas )
{
    if (curLevel_ != 0)
        curLevel_->DrawLevel(canvas);
}
bool SystemState::onKey(const IKeyEvent::KeyEvent& key_event)
{
    //for testing purposes
    if(key_event.key_state == IKeyEvent::KeyEvent::KB_DOWN && key_event.key == IKeyEvent::KeyEvent::KB_SPC_KEY)
    {
        LoadLevel(std::string("resources/files/level2.txt"));
    }
    if(key_event.key_state == IKeyEvent::KeyEvent::KB_DOWN && key_event.key == IKeyEvent::KeyEvent::KB_ESC_KEY)
    {
        application.exit();
        return false;
    }

    return true;
}
void SystemState::LoadLevel(std::string filePath)
{
    curLevel_ = new Level(filePath); //segmentation fault
}
//Level.cpp
Level::Level(std::string filePath)
{
    SnakeFileReader sfr(filePath);
    ImageFile(sfr.ReadLine()).load(map_layout);
    mapWidth_ = sfr.ReadInt();
    mapHeight_ = sfr.ReadInt();
    level_cell_size_ = sfr.ReadInt();

    map_ = new TileData*[mapWidth_];

    for (int i = 0; i < mapWidth_; i++)
    {
        map_[i] = new TileData[mapHeight_];
    }

    int numUnwalk = 0;

    bool foundPlayerDZ = false;
    bool foundEnemyDZ = false;
    Vector3 playerDZStart;
    Vector3 enemyDZStart;

    int iterations = sfr.ReadInt();
    TileInfo mapTiles[iterations];
    for (int i = 0; i < iterations; i++)
    {
        mapTiles[i].filePath = sfr.ReadLine();
        mapTiles[i].readColour = Colour(sfr.ReadColour());
        mapTiles[i].canWalk = sfr.ReadInt();
    }

    bool test = false;

    for (int y = 0; y < mapHeight_; y++)
    {
        for (int x = 0; x < mapWidth_; x++)
        {
            Colour cellColour = map_layout.getPixel(x * level_cell_size_, y * level_cell_size_);
            for (int i = 0; i < iterations; i++)
            {
                if (IsSameColour(cellColour, mapTiles[i].readColour))
                {
                    test = true;
                    ImageFile(mapTiles[0].filePath).load(map_[x][y].tile);
                    if (!mapTiles[i].canWalk)
                    {
                        Image wall;
                        ImageFile(mapTiles[i].filePath).load(wall);
                        wall.setTransparentColour(Colour(255,0,255));
                        map_[x][y].tile.blit(wall);
                        unwalkableLocs_.push_back(Vector3(x, y, 0));
                        numUnwalk++;
                    }
                }
            }

            if (IsSameColour(cellColour, humanDropZone_))
            {
                test = true;
                if (!foundPlayerDZ)
                {
                    playerDZStart = Vector3(x,y,0);
                    foundPlayerDZ = true;
                }
                ImageFile(mapTiles[0].filePath).load(map_[x][y].tile);
            }
            else if (IsSameColour(cellColour, computerDropZone_))
            {
                test = true;
                if (!foundEnemyDZ)
                {
                    enemyDZStart = Vector3(x,y,0);
                    foundEnemyDZ = true;
                }
                ImageFile(mapTiles[0].filePath).load(map_[x][y].tile);
            }
        }
    }
    human_ =  new Player(sfr.ReadVector(), Size(level_cell_size_,level_cell_size_), HUMAN, this, sfr.ReadLine());
    computer_ = new Player(sfr.ReadVector(), Size(level_cell_size_,level_cell_size_), COMPUTER, this, sfr.ReadLine(), human_);
    human_->SetOpponent(computer_);
    computer_->SetupDropZone(enemyDZStart);
    human_->SetupDropZone(playerDZStart);
    SetupCollectables();
}

Can anyone see why? If I didn't de-allocate memory on the heap from the previous level could that cause this problem? I have been putting off creating all the destructors for the classes created by the level. Maybe that's the problem?

Thanks in advance

[LB]

If you create something with new, you must at some point destroy it with delete.
If you create something with new[], you must at some point destroy it with delete[].

I hit ctrl+f on this page and search for "delete" and there were no results in your code.

[martianxx]

This is not the whole code, only a small part of it that I believed the error may be getting caused in. So you think that the problem could be caused by not de-allocating memory stored in the heap?

[LB]

martianxx wrote:

I want to delete that pointer [...] However when I do this I get a segmentation fault.

You claim that the segmentation fault occurs when you delete the pointer, however there is no "delete" in the code you posted.

[kooth]

I'd go with L B on checking for the deletes.

Also, when you call LoadLevel(), you aren't checking to see if curLevel_ is already allocated. You should check it and delete it if it isn't NULL in that function.

[LB]

@kooth for that to work he'd have to have nulled out the pointer in the first place, which some programmers don't do (see "dangling pointer")

[martianxx]

You claim that the segmentation fault occurs when you delete the pointer, however there is no "delete" in the code you posted.

Sorry for the confusion. I meant that it occurs when the level is loaded. I had in my head it could be to do with memory de-allocation which based on your posts seems to be a reasonably assumption.

If the pointer is not null when I delete it what would the implications be? I assume none (with the right destructors for the classes used by in level in place) as long as I re-assign it straight away to avoid a dangling pointer.