The library interface (`cs50.h`) and the implementation (`cs50.c`) needs to be compiled into either a _library object file_ (`.o`), a _shared object file_ (`.so`), or an _archive file_ (`.a`) in order to be linked into other programs. The following command should yield an object file that could be statically linked it into other programs assuming both `cs50.h` and `cs50.c` are present in the current working directory. `cc -c -o cs50.o cs50.c` The resulting object file (`cs50.o`) should then be placed ideally under `/usr/local/lib/` while the implementation file (`cs50.h`) should be placed under `/usr/local/include/` with `644` permission preferably. Alternately, following the instructions outlined at [cs50/libcs50](https://github.com/cs50/libcs50#from-source-linux-and-mac) will yield an equivalent denouement but with relatively less complication.