There are many Java examples for LibreOffice SDK that are listed here:
On the other hand, there are few C++ examples. Port Java examples to C++. All the examples are listed here:
Hossein committed a patch related to this issue.
It has been pushed to "master":
tdf#143122 - Port Java examples to C++
It will be available in 7.4.0.
The patch should be included in the daily builds available at
https://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More
information about daily builds can be found at:
Affected users are encouraged to test the fix and report feedback.
Re-evaluating the EasyHack in 2022
This EasyHack is still relevant. There are many SDK examples that can be ported to C++, and can be also added to the DevGuide:
LibreOffice Developer's Guide