STL 映射到自身? [英] STL map onto itself?

问题描述

我想创建一个 std::map，其中包含一个 std::vector 迭代器，以实现一个简单的基于邻接列表的图形结构.

但是，类型声明让我很困惑:您似乎需要整个映射类型定义来获取所述映射的迭代器类型，如下所示:

地图
int, 东西 >::iterator MyMap_it;//Something 应该是什么?地图
是否有某种部分映射迭代器类型我可以只使用键类型来获得，所以我可以声明完整映射?
解决方案
你可以使用新类型的前向声明.
类 MapItContainers;typedef map::iterator MyMap_it;类 MapItContainers{上市:矢量<MyMap_it>向量；};
使用这种间接方式，编译器应该可以让你摆脱它.它不是很漂亮，但老实说，我认为你不能轻易打破自我引用.
I'd like to create a std::map that contains a std::vector of iterators into itself, to implement a simple adjacency list-based graph structure.  

However, the type declaration has me stumped: it would seem you need the entire map type definition to get the iterator type of said map, like so:
map< int, Something >::iterator MyMap_it;  // what should Something be?
map< int, vector<MyMap_it> > MyMap_t;
Is there some sort of partial map iterator type I can get with just the key type, so I can declare the full map?
解决方案
You could use forward declaration of a new type.
class MapItContainers;
typedef map<int, MapItContainers>::iterator MyMap_it;

class MapItContainers
{
public:
 vector<MyMap_it> vec;
};
With this indirection the compiler should let you get away with it.
It is not so very pretty but honestly I don't think you can break the self referencing easily.

                        
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