alternating string replace

[bearophileHUGS at lycos.com]

Gordon C:
> This is very cool stuff but I suspect that the code is unreadable
> to many readers, including me. Just for fun here is a complete program,
> written in  Turbo Pascal, circa 1982, that does the job. Readable
> n'est pas?

I think it's quite readable, especially if you indent it more
correctly.
Pascal is usually among the most readable languages, for not-too-much
complex tasks. I don't mind its mutable strings too much.

Bye,
bearophile