How to initialize C++17 vector of pairs with optional element

Question

In C++17, how do you declare and initialize a vector of pairs(or tuples) with an optional element?

    std::vector<std::pair<int, optional<bool> > > vec1 = { {1, true},                                                            {2, false},                                                             {3, nullptr}}; 

I have a pair where the second element may be null/optional.

Answer 1

You are looking for std::nullopt instead of nullptr.

std::vector<std::pair<int, std::optional<bool> > > vec1 =   { {1, true}, {2,false}, {3,std::nullopt} };