This is just terrific stuff, tye. Like tilly's criticisms, I understand what you wrote, and I can agree with everything you said. I'm grateful that you both took so much time to make detailed comments. I'll try to make good use of your advice, not just in improving this simple program but in thinking more carefully about portability, maintainability, and choosing the appropriate data structures.
Hopefully the light will come up, little by little, and
you'll see some smarter programs from me over time!