Modifying the code as you said ACE works perfectly well with c and cpp question type.
Before I post a question on the forum I tried a lot of things related to this problem:
- to apply a custom css for the current theme mentioned in the post on the link https://coderunner.org.nz/mod/forum/discuss.php?d=27,
- also try to change default theme for Moodle but nothing happens.
-From this link: https://github.com/ajaxorg/ace-builds test all ace-builds for ace:
Every time I did some changes I always perform clear theme cache and purge all cache, but without success.
Once again, thanks Richard.