What type does auto use for containers?

Question

I can achieve identical output by using different containers in C++. For example . .

    std::array<int, 5> v = {1,2,3,4,5};
    for(auto i : v)
        std::cout << i << ", ";

or

    std::vector<int> v = {1,2,3,4,5};

or

    int v[] = {1,2,3,4,5};

etc . .

So what container does auto use here?

    auto v = {1,2,3,4,5};
    for(auto i : v)
        std::cout << i << ", ";

Answer 1

std::initializer_list<int>

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Not that hard to check for yourself, you can always decltype(v), and then compare it with said list type.

That has another nice property, that sometimes is very useful and might interest you:

for (auto i : {1,2,3,4,5})
    std::cout << i << ", ";

It can be done because initializer_list keeps the standard range interface.