siv::IndexedIterator is a header-only indexed iterator library for modern C++.
std::vector<int> v = { 0, 100, 200, 300, 400, 500 };
for (auto [i, n] : Indexed(v))
{
std::cout << i << ": " << n << "\n";
} 0: 0
1: 100
2: 200
3: 300
4: 400
5: 500
std::string s = "Hello, world!";
for (auto [i, ch] : Indexed(v))
{
std::cout << i << ": " << ch << "\n";
}0: H
1: e
2: l
3: l
4: o
5: ,
6:
7: w
8: o
9: r
10: l
11: d
12: !
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";
} 0: aaa, AAA
1: bbb, BBB
2: ccc, CCC
siv::IndexedIterator is distributed under the MIT license.