C ++ STL映射我不想让它排序！ [英] C++ STL map I don't want it to sort!

问题描述

这是我的代码

map<string,int> persons;

persons["B"] = 123;
persons["A"] = 321;


for(map<string,int>::iterator i = persons.begin();
    i!=persons.end();
    ++i)
{
    cout<< (*i).first << ":"<<(*i).second<<endl;
}

预期输出：

  B:123
  A:321

但它的输出是：

  A:321
  B:123

我想让它保持键和值插入 map的顺序。

I want it to maintain the order in which keys and values were inserted in the map<string,int>.

有可能吗？还是应该使用一些其他的STL数据结构？哪一个？

Is it possible? Or should I use some other STL data structure? Which one?

推荐答案

没有标准容器直接做你想要的。使用明显的容器，如果你想维护插入顺序是一个向量。如果还需要通过字符串查找，请使用向量和映射。映射通常是字符串到向量的索引，但是因为你的数据已经是整数，你可能只是想复制它，这取决于你的用例。

There is no standard container that does directly what you want. The obvious container to use if you want to maintain insertion order is a vector. If you also need look up by string, use a vector AND a map. The map would in general be of string to vector index, but as your data is already integers you might just want to duplicate it, depending on your use case.

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