These examples can be built by saying, in the build directory,
make examples
The resulting binaries will be placed in build/examples/c++.
The examples can also be compiled by hand. The basic.cc example can be
compiled as:
g++ -std=c++17 -c basic.cc
g++ -o basic basic.o -L/usr/local/lib/opencog -latom_types -latombase -latomspace
To run it, just say:
$ ./basic