The yp-client C++ code examples are installed in /usr/share/yumapro/src/yp-client
Make sure to install the yumapro-pthreads version of the DEB or RPM package.
Only the yumapro-pthreads packages include the yp-client code examples since yp-client requires pthreads support.
Example of a yumapro-pthreads package:
From Top-Level Makefile:
### only try to install the yp-client examples if PTHREADS=1 set ifdef PTHREADS DIRS += yp-client endif # PTHREADS