问题描述
我想知道，如何为STL迭代器建立等号（==）？
I was wondering, how is equality (==) established for STL iterators?Is it a simple pointer comparison (and thus based on addresses) or something more fancy?
如果我有两个不同的列表对象的两个迭代器，我比较他们，结果总是假的？
If I have two iterators from two different list objects and I compare them, will the result always be false?
如果我将有效值与超出范围的值进行比较怎么办？
What about if I compare a valid value with one that's out of range? Is that always false?
推荐答案
迭代器类可以定义重载的==操作符，如果他们想要的话。所以结果取决于 operator == 的实现。
Iterator classes can define overloaded == operators, if they want. So the result depends on the implementation of operator==.
你实际上不应该比较迭代器不同的容器。我认为一些调试STL实现会发出警告，如果你这样做，这将帮助你捕获这种错误使用的代码中的情况。
You're not really supposed to compare iterators from different containers. I think some debug STL implementations will signal a warning if you do this, which will help you catch cases of this erroneous usage in your code.
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