A high-level, general-purpose programming language, created as an extension of the C programming language, that has object-oriented, generic, and functional features in addition to facilities for low-level memory manipulation.
as writing a webserver is complex, you would probably pick a web framework. see for example some popular ones:
https://www.treefrogframework.org
https://www.webtoolkit.eu/wt
https://crowcpp.org/master/
https://drogon.org