通过for循环从C ++映射中删除元素 [英] Removing elements from a C++ map through a for-loop

问题描述

我的STL有点生锈，所以请原谅我问一个可能琐碎的问题。考虑下面的代码：

My STL is a bit rusty, so forgive me for asking a possibly trivial question. Consider the following piece of code:

map<int,int> m;
...
for (auto itr = m.begin(); itr != m.end(); ++itr) {
    if (itr->second == 0) {
        m.erase(itr);
    }
}

问题是：循环地图？

推荐答案

我认为你不应该使用删除的迭代器 - 如果列表这会导致严重的问题，对于地图而言是不同的。

I think that you shouldn't use removed iterator at all - in case of lists this causes serious problems, shouldn't be different for maps.

EDIT by Matthieu M：这段代码在C ++ 0x中格式良好， 。

EDIT by Matthieu M: this code is well-formed in C++0x and allowed as an extension by MSVC.

map<int,int> m;
...
auto itr = m.begin();
while (itr != m.end())
{
    if (itr->second == 0) {
        itr = m.erase(itr);
    }
    else 
    {
        itr++;
    }
}

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