STL对set之类的容器begin／end做--/++操作的结果没有规定？

fender0107401

回复 8# hellioncu

嘿嘿，我的C++也就是满足自己使用的水平啊。
   

shang2010

感觉现在cpp这帮人对vs有歧视，什么标准建议的都不带vs玩，
vs就写vs自己的代码，别理会这些异常不兼容现象

folklore

       set<int>::iterator it = s.begin();
        --it;
        if (it == s.end())

这地方怕是访问了 operator==而不是地址比较

回头再说了

看不明白～～～～～～····

幻の上帝

WG21/N4527

24.2.1 In general [iterator.requirements.general]

7 An iterator j is called reachable from an iterator i if and only if there is a finite sequence of applications of
the expression ++i that makes i == j. If j is reachable from i, they refer to elements of the same sequence.
8 Most of the library’s algorithmic templates that operate on data structures have interfaces that use ranges.
A range is a pair of iterators that designate the beginning and end of the computation. A range [i,i) is an
empty range; in general, a range [i,j) refers to the elements in the data structure starting with the element
pointed to by i and up to but not including the element pointed to by j. Range [i,j) is valid if and only if
j is reachable from i. The result of the application of functions in the library to invalid ranges is undefined.