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What would a std::map extended initializer list look like?

Posted by: admin November 29, 2017 Leave a comment

Questions:

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

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

Answers:

It exists and works well:

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

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.

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

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