如何从迭代器获取列表

Question

How can I get a list from an iterator ?

std::list<int> list;
auto it1 = list.insert(list.end(), 1);
auto it2 = list.insert(list.end(), 2);
auto it3 = list.insert(list.end(), 3);
auto it4 = list.insert(list.end(), 4);
auto it5 = list.insert(list.end(), 5);

list.erase(it3);

In included code, I am able to erase it3 from the list. What if I know only an iterator, can an iterator erase itself from the list without having the list variable ?

//Something like that
it2.list.erase(it2);

Answer 1

Technically it is possible to erase element in Doubly linked list and update neighboring nodes links after erasure. But std::list also maintains it's size() , which must run in O(1) since C++11. So it is impossible to update the list size without accessing list itself.

Answer 2

如文档 std::list::iterator满足BidirectionalIterator概念，因此您可以看到，这两个概念都不是，它的祖先具有获取其所属容器的功能。

Answer 3

You can't get the list from an iterator, you can obtain the iterator from the list. The std::list container has an erase member function, iterator does not, so no, it can not erase itself. If you know the iterator, supply it to the list's erase function. As pointed out in the comments you should not name your variable list , especially if you have using namespace std; statement somewhere in your code which is also to be avoided.