The following code example is taken from the book
C++20 - The Complete Guide by Nicolai M. Josuttis, Leanpub, 2021
The code is licensed under a Creative Commons Attribution 4.0 International License. Creative Commons License

// raw code

#include "chronoparse.hpp"
#include <iostream>

int main()
  auto tp1 = parseDateTime("2021-1-1");
  std::cout << std::format("{:%F %T %Z}\n", tp1);

  auto tp2 = parseDateTime<std::chrono::local_t>("2021-1-1");
  std::cout << std::format("{:%F %T}\n", tp2);

  auto tp3 = parseDateTime<std::chrono::utc_clock>("2015-6-30 23:59:60");
  std::cout << std::format("{:%F %T %Z}\n", tp3);

  auto tp4 = parseDateTime<std::chrono::gps_clock>("2021-1-1 18:30");
  std::cout << std::format("{:%F %T %Z}\n", tp4);