什么std :: map扩展初始化列表看起来像？ [英] What would a std::map extended initializer list look like?

问题描述

如果它甚至存在，std :: map扩展初始化列表会是什么样子？

If it even exists, what would a std::map extended initializer list look like?

我试过一些组合...好，一切我

I've tried some combinations of... well, everything I could think of with GCC 4.4, but found nothing that compiled.

推荐答案

它存在和工作良好：

std::map <int, std::string>  x
  {
    std::make_pair (42, "foo"),
    std::make_pair (3, "bar")
  };

请记住，地图的值类型是 pair< const key_type，mapped_type> ; ，所以你基本上需要一个具有相同或可转换类型的对的列表。

Remember that value type of a map is pair <const key_type, mapped_type>, so you basically need a list of pairs with of the same or convertible types.

通过使用std :: pair的统一初始化，代码变得更简单

With unified initialization with std::pair, the code becomes even simpler

std::map <int, std::string> x { 
  { 42, "foo" }, 
  { 3, "bar" } 
};

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