问题描述
我发现 std :: set 上的更新操作很乏味，因为。因此，我目前正在执行的操作是这样的：
I find the update operation on std::set tedious since there's no such an API on cppreference. So what I currently do is something like this:
//find element in set by iterator
Element copy = *iterator;
... // update member value on copy, varies
Set.erase(iterator);
Set.insert(copy);
基本上， Set 的迭代器返回是 const_iterator ，您不能直接更改其值。
Basically the iterator return by Set is a const_iterator and you can't change its value directly.
是否有更好的方法？或者也许我应该通过创建自己的方法来覆盖 std :: set （我不知道它是如何工作的。）
Is there a better way to do this? Or maybe I should override std::set by creating my own (which I don't know exactly how it works..)
推荐答案
set 返回 const_iterators （标准说 set< T> :: iterator 是 const ，而 set< T> :: const_iterator 和 set< T> :: iterator 实际上可能是同一类型-参见n3000.pdf中的23.2.4 / 6），因为它是订购的容器。如果它返回常规的 iterator ，则允许您从容器下方更改项目的值，从而可能更改顺序。
set returns const_iterators (the standard says set<T>::iterator is const, and that set<T>::const_iterator and set<T>::iterator may in fact be the same type - see 23.2.4/6 in n3000.pdf) because it is an ordered container. If it returned a regular iterator, you'd be allowed to change the items value out from under the container, potentially altering the ordering.
您的解决方案是更改集合中项目的惯用方式。
Your solution is the idiomatic way to alter items in a set.
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