{

auto op1 = std::make_optional<std::vector<char>>({'a','b','c'});

std::cout << "op1: ";

for (char c: op1.value()){

std::cout << c << ",";

}

auto op2 = std::make_optional<std::vector<int>>(5, 2);

std::cout << "\nop2: ";

for (int i: *op2){

std::cout << i << ",";

}

std::string str{"hello world"};

auto op3 = std::make_optional<std::string>(std::move(str));

std::cout << "\nop3: " << quoted(op3.value_or("empty value")) << '\n';

std::cout << "str: " << std::quoted(str) << '\n';