std::vector<int> v = { 0, 100, 200, 300, 400, 500 };

for (auto [i, n] : Indexed(v))
{
	std::cout << i << ": " << n << "\n"; 
}  

std::string s = "Hello, world!";

for (auto [i, ch] : Indexed(v))
{
	std::cout << i << ": " << ch << "\n"; 
}

std::map<std::string, std::string> m = { { "aaa", "AAA" }, { "bbb", "BBB" }, { "ccc", "CCC" } };

for (auto [i, p] : Indexed(m))
{
	std::cout << i << ": " << p.first << ", " << p.second << "\n"; 
}