Which IP Adress i have to use?

[Felix91]

i wrote a program and with my local ip address all works fine to me but i gave the program another person and he told me that the connection to the server failed so i tried with my public address but than also on my computer the connection to the server failed. Now I dont know which IP address i have to use.
Can someone explain me it?

[eXpl0it3r]

I suggest to read up about how IPs "work" and what NAT does.
Additionally you should check out the FAQ on that topic: https://www.sfml-dev.org/faq.php#network-internet-network