How to convert time from GMT to Kiev taking into account the winter / summer period?

Question

C++ / C#

Hello everyone,
Something I'm completely confused with this time. Belts, offsets, etc., I read a lot of sources, my head is spinning. Perhaps someone has already encountered this simple task. It is necessary to convert the time from GMT to Kiev, taking into account the winter / summer period. Share the code, or a good article on this topic.
Thanks a lot.