如何从 STL 的 const_iterator 中获取数据？
我有这样运行的东西：
T baseline;
list<T>::const_iterator it = mylist.begin();
while (it != mylist.end()) {
if (it == baseline) /* <----- This is what I want to make happen */
// do stuff
}
我的问题是我不知道如何从迭代器中提取数据。我觉得这是一件愚蠢的事情，令人困惑，但我不知道该怎么做。
编辑：修复了 begin.end()
I have something that runs like this:
T baseline;
list<T>::const_iterator it = mylist.begin();
while (it != mylist.end()) {
if (it == baseline) /* <----- This is what I want to make happen */
// do stuff
}
My problem is that I have no idea how to extract the data from the iterator. I feel like this is a stupid thing to be confused about, but I have no idea how to do it.
EDIT : Fixed begin.end()
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迭代器有一个“看起来”像指针的接口（但它们不一定是指针，所以不要用这个比喻太过分）。
迭代器表示对容器中单个数据的引用。您想要的是在迭代器指定的位置访问容器的内容。您可以使用
*it访问it位置的内容。同样，您可以使用it->method()对位于it位置的内容（如果内容是对象）调用方法。这与您的问题并不真正相关，但这是一个需要注意的常见错误（即使我仍然时不时地犯）：如果位置
it处的内容是 < em>指向对象的指针，要调用对象的方法，语法为(*it)->method()，因为有两级间接。Iterators have an interface that "looks" like a pointer (but they are not necessarily pointers, so don't take this metaphor too far).
An iterator represents a reference to a single piece of data in a container. What you want is to access the contents of the container at the position designated by the iterator. You can access the contents at position
itusing*it. Similarly, you can call methods on the contents at positionit(if the contents are an object) usingit->method().This doesn't really relate to your question, but it is a common mistake to be on the lookout for (even I still make it from time to time): If the contents at position
itare a pointer to an object, to call methods on the object, the syntax is(*it)->method(), since there are two levels of indirection.使用迭代器的语法与使用指针的语法基本相同。要获取迭代器“指向”的值，您可以使用
*进行取消引用：如果列表是对象列表，您还可以使用
->< 访问对象的方法和属性/代码>：The syntax to use an iterator is basically the same as with a pointer. To get the value the iterator "points to" you can use dereferencing with
*:If the list is a list of objects you can also access methods and properties of the objects with
->:使用：
Use:
使用 *it 来访问迭代器所指向的元素。当你比较时我想你应该使用 if (*it == 基线)
Use *it to access the element pointed by the iterator. When you are comparing i guess you should use if (*it == baseline)
std 迭代器重载了operator*()，这样您就可以像访问指针一样访问引用的位置。
the std iterators overload the operator*(), this way you can access the referenced location the same way as if it was a pointer.
据我所知，std 迭代器不是指针，而是指向底层单个数据元素的实际指针的薄包装。
你可以使用
某事=*它访问迭代器指向的元素。
*it==baseline 是这种行为的正确代码。
另外，如果您正在处理 STL 中的集合，您可以考虑使用诸如
find_if之类的函数http://www.cplusplus.com/reference/algorithm/find_if/
from what i know std iterators are not pointers, but are a thin wrapper around the actual pointers to the underlying individual data elements.
you can use
something=*itto access an element pointed by the iterator.
The *it==baseline is a correct code for that kind of behaviour.
Also if you are dealing with collections from STL you can consider using functions such as
find_ifhttp://www.cplusplus.com/reference/algorithm/find_if/