移除和删除与向量中的条件匹配的指针

Question

我有一个std::vector我想从满足条件的向量中删除指针isDestroyed()，但还要对指针调用 delete 。

我做了以下操作，但它需要对向量循环两次。有没有更有效的方法来做到这一点？

std::vector<GameObject*> gameObjects;
std::vector<GameObject*> destroyedObjects;
// Get objects to be deleted
std::copy_if (gameObjects.begin(), gameObjects.end(), std::back_inserter(destroyedObjects), [](GameObject* b){return b->isDestroyed();} );
// Remove objects from vector
gameObjects.erase(
    std::remove_if(
            gameObjects.begin(),
            gameObjects.end(),
            [](GameObject* p) { return p->isDestroyed(); }
    ),
    gameObjects.end()
);
// Delete the objects
for (GameObject* o : destroyedObjects)
    delete o;

Answer 1

这应该有效：

std::vector<GameObject*> gameObjects;
auto end = std::stable_partition(
            gameObjects.begin(),
            gameObjects.end(),
            [](GameObject* p) { !return p->isDestroyed(); }
    );
for (auto i = end; i < gameObjects.end(); i++) {
    delete *i;
}
gameObjects.erase(end, gameObjects.end());

Answer 2

std::unique_ptr 免费删除：

std::vector<std::unique_ptr<GameObject>> gameObjects;

// Remove objects from vector
gameObjects.erase(
    std::remove_if(
            gameObjects.begin(),
            gameObjects.end(),
            [](const auto& p) { return p->isDestroyed(); }
    ),
    gameObjects.end()
);

我建议改用它。它还避免了忘记删除或重复删除等错误。