list iterator not incrementable

[2NywAqkS]

I'm following this tutorial: http://devmaster.net/posts/3232/how-to-structure-a-game

After reading this I wrote a practice program and my problem came when I wanted to delete something from the list. Here is my program.

#include <iostream>
#include <list>

class Apple
{
private:
	static std::list <Apple *> applePtrVector;
	std::list <Apple *>::iterator iterator;

	void Destroy();
public:
	Apple();
	~Apple();

	static void DestoryAll();
};

void Apple::Destroy()
{
	delete this;
}

Apple::Apple()
{
	applePtrVector.push_front(this);
	this->iterator = applePtrVector.begin();
}

Apple::~Apple()
{
	applePtrVector.erase(this->iterator);
}

void Apple::DestoryAll()
{
    for (std::list <Apple *>::iterator i = applePtrVector.begin(); i != applePtrVector.end(); i++)
    {
		(*i)->Destroy();
    }
}

std::list <Apple *> Apple::applePtrVector;

int main()
{
	new Apple;
	new Apple;
	new Apple;
	new Apple;
	Apple::DestoryAll();
	return 0;
}

On the first call of 'delete this' I get the error "list iterator not incrementable". I realise I could use applePtrVector.clear but what if I needed to call 'delete this' in an update function?

Thanks,
Rowan.

[vlad from moscow]

Try the following

void Apple::DestoryAll()
{
    for (std::list <Apple *>::iterator i = applePtrVector.begin(); i != applePtrVector.end(); /* empty */ )
    {
		(*i++)->Destroy();
    }
}

[2NywAqkS]

Haha, works perfect thanks! But why?

[SirSmilesaLot]

cant believe!!!

[vlad from moscow]

@Rowan836

Haha, works perfect thanks! But why?

Because before deleting a node you get the next valid iterator by using the postincrement.

In your original code after deleting a node the iterator becames invalid.