Thought I'd also have a go at translating ch-1.pl and ch-2.c into C..

Both ch-1.c and ch-2.c produce identical (non-debugging) output to my
Perl originals.

Both use the command-line argument processing module args.[ch].
I translated IsPrime.pm to isprime.[ch], and wrote an array printing
function in prarray.[ch].

Both tasks were very straightforward to translate, it's just that
we have to write a lot more low-level support code that Perl does
for us..