Update C example with more realistic usage
Update C example with more realistic usage

Luthaf/Chemharp,lscalfi/chemfiles,chemfiles/chemfiles,Luthaf/Chemharp,lscalfi/chemfiles,Luthaf/Chemharp,chemfiles/chemfiles,lscalfi/chemfiles,lscalfi/chemfiles,chemfiles/chemfiles,chemfiles/chemfiles