CODEWITHSUNDEEP
c++visual-studiolistvisual-studio-2015iterator
Branislav Krajčo
Branislav Krajčo

Reputation: 5

"List iterators incompatible" while running

void GameLogic::isHit(int mousePressX, int mousePressY) 
{

for each(BallObject* ball in ballList) {
    for (it = ballList.begin(); it != ballList.end();)
    {
        bool isHit = ball->EvaluateHit(mousePressX, mousePressY);
        if (isHit == true)
        {
            mScore++;
            ballList.remove(ball);
        }
        else
        {
            ++it;
        }
    }
}

I am trying to remove ball from "ballList" while playing game via click on surface(ball should dissapear). Program is running correctly until click. When I click, it gives an error from the title. How does it right?

Upvotes: 0

Views: 66

Answers (1)

Chad
Chad

Reputation: 19032

void GameLogic::isHit(int mousePressX, int mousePressY) 
{
    // iterate all the balls in the list...
    for (it = ballList.begin(); it != ballList.end();)
    {
        bool isHit = (*it)->EvaluateHit(mousePressX, mousePressY);

        if (isHit == true)
        {
            mScore++;
            // This invalidates iterators, and is linear in complexity
            // (it iterates the list too, but you're already doing that)
            // ballList.remove(ball);

            // erase the ball at this iteration, save off the result
            // so you can continue iterating
            it = ballList.erase(it);
        }
        else
        {
            // if the ball wasn't hit, increment the iterator normally
            ++it;
        }
    }
}

Upvotes: 2

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