C ++删除对象

Question

Does the delete() operator destroy all the sub-objects of an object too? Or do I need to call the delete of sub-object before deleting the parent object?

class equipment
{
   public:
     int model_id;
     ...
}

class player
{
   public:
     int x, y;
     equipment * Equipment; 
     player(void) { Equipment = new equipment[2];};
     ~player(void) { delete [] Equipment; }
};

int main (....)
{
  player = new Player;
  ...
  ...
  delete Player;
}

Answer 1

您需要在主对象的析构函数中删除动态分配的子对象，并且已通过删除数组Equipment正确地完成了此操作

Answer 2

Delete operator does delete all "subobjects" as you say, but usually and in your case you need to delete not only "sub objects" but also memory, where member pointers point to. So if you used vector object, for example, it would be deleted automatically, but in this case you need to delete it explicitly, which you did correctly

Answer 3

To put it simply, during destruction of the object :

• Member objects are themselves destroyed
• Objects pointed by member pointers aren't

That means that you have to delete them manually (like your Equipement pointer), if you own them . There might be case when your class ends up with a pointer it does not own (for example, a handle to some other object you need in this class), and thus should not delete.

You can use smart pointers (ie: std::shared_ptr , std::unique_ptr , etc.) to manage memory in a safer way (they, notably, automatically delete the pointers they manage, following the RAII principle ).

Answer 4

您缺少的一件事是一流设备中的析构函数

Answer 5

The stuff you do in your example is sufficient, you

delete[] Equipment;

in the destructor of player, so all contained equipments will be deleted as soon as a player gets deleted.

Nicely done!