删除std :: list的内容

Question

I have a list of pointers which I don't need anymore. To delete all of them, I can normally iterate the list:

for (T* ptr: mylist) {
    delete ptr;
}

Or I can delete the first or last element until the list is empty:

while (!mylist.empty()) {
    delete mylist.front(); //or mylist.back()
    mylist.pop_front(); //or mylist.pop_back()
}

What is the preferred way, both for performance and clarity?

Answer 1

The best way is to store std::unique_ptr's in list and not manage memory yourself. Then you just do mylist.clear() .

Answer 2

They do two different things. The second leaves you with an empty list. The first leaves you with a list that holds a bunch of invalid pointers; that may or may not matter, depending on what happens to the list after this operation.

Answer 3

I would use your first example. For best practice you should clear your list afterwards to ensure no invalid pointers are left in it.

for (T* ptr : mylist) delete ptr;
mylist.clear();