Question

I have got this Runtime Error when running this code:

void AlienShipManager::Update(float timeDelta, 
        BulletManager* bulletManager,
        ParticleManager* particleManager,
        GameStringSystem* stringBatch)
{
    unsigned int i = 0;
    while (i < m_alienShipList.size())
    {
        AlienResult result = m_alienShipList[i].Update(timeDelta, bulletManager);
        switch (result)
        {
            case AlienResult::Dead:
                break;
            default:
                break;
        }
            ++i 
    }
}

in line

AlienResult result = m_alienShipList[i].Update(timeDelta, bulletManager);

There is how I add AlienShip to vector class:

m_alienShipList.push_back(AlienShip(position, speed, m_screeSize, m_alienShipTexture));

error also appers if I chance that to:

AlienShip* newAlien = new AlienShip(position, speed, m_screeSize, m_alienShipTexture);
    m_alienShipList.push_back(*newAlien);
    delete newAlien;

but does not appear if I change that to:

AlienShip* newAlien = new AlienShip(position, speed, m_screeSize, m_alienShipTexture);
    m_alienShipList.push_back(*newAlien);

which hence lead to huge memory leaks.

This is how looks my AlienShip class:

#pragma once

#include "Body.h"
#include "BulletManager.h"
#include "ParticleManager.h"

enum AliensShipState
{
    flying,
    dying,
    dead,
    escaped
};

enum AlienResult
{
    No,
    Hit,
    Dying,
    Dead,
    Escaped
};

class AlienShip : public Body
{
public:
    AlienShip(void);
    AlienShip(float2& position, float2& speed, float2* screenSize, ID3D11Texture2D* alienTexture);
    ~AlienShip(void);

    AlienResult Update(float timeDelta, BulletManager* bulletManager);
    void Draw(BasicSprites::SpriteBatch^ spriteBatch);

protected:
    float m_baseY;
    AliensShipState m_state;
    float2* m_screenSize;
};

AlienShip class is inherited from Body class, which has Sprite class inside it, which has another vector inside it.
But since Sprite class is working perfectly elsewhere, I don’t think it is source of error.

I wonder why this happens, because I can’t find the relationship between deleting temporary object and corrupting vector iterator, If it corrupted at all.

Also program compiles and runs in Release, but with some data corruption.

I am using Visual Studio 2012 Beta for Windows 8.

Please write if you need more source code.
Unfortunately it is very hard to post all code, as this is complex program.

Answer 1

Given that it doesn’t work when you add the item to the vector by value but it does when you leak a pointer, I have 95% confidence that your copy constructor for AlienShip does a shallow copy, causing your problems.

EDIT: Note that m_alienShipList.push_back(AlienShip(position, speed, m_screeSize, m_alienShipTexture)); causes a copy of your class and if the copy constructor doesn’t work right it will cause problems later.

In fact if the AlienShip definition you’ve pasted is correct there is in fact only the default copy constructor which likely does the wrong thing (further reinforced by the fact that you have your own destructor).

Either implement a copy constructor that does a deep copy, or more preferably rewrite your class to use RAII to manage the memory for you so that the default copy is correct.