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

Question

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.

Solution

I'd like to add to doublep's answer that list initialization also works for nested maps. For example, if you have a std::map with std::map values, then you can initialize it in the following way (just make sure you don't drown in curly braces):

int main() {
    std::map<int, std::map<std::string, double>> myMap{
        {1, {{"a", 1.0}, {"b", 2.0}}}, {3, {{"c", 3.0}, {"d", 4.0}, {"e", 5.0}}}
    };

    // C++17: Range-based for loops with structured binding.
    for (auto const &[k1, v1] : myMap) {
        std::cout << k1 << " =>";
        for (auto const &[k2, v2] : v1)            
            std::cout << " " << k2 << "->" << v2;
        std::cout << std::endl;
    }

    return 0;
}

Output:

1 => a->1 b->2
3 => c->3 d->4 e->5

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