Programming

OK, after checking, I should admit, that I was wrong!
Corrona688, you ar ecompletely right, and I am not able to use 'enum' like 'maping' definition to indexes of info-struct array!
No way to refer a label by a string: that what was in my mind when I said that I can do it for string - integer relation.

Thus, I do not see a way to get dirrect referensing in form of associative aray without or search processing on each request, or look-up or maping array, that makes solution not sparse (and for int-int makes no sence: same type!)

Thank you for dissucing it with me and letting realize it!

If you wanted a truly sparse solution I already gave you that. Even if it was done by the compiler, it'd still need to search somehow if it didn't use a big table. It's not psychic either, after all. You wanted a solution with guaranteed fixed search time, which even hash tables can't do. It has to be an array.

256 integer elements is one kilobyte of memory. That's not a lot. It can fit in a modern processor's cache many times over. And if you know you have fewer elements, you can make it smaller.

I think it makes plenty of sense to use an array. You see it happen all the time. When you build a processor using the lex and yacc tools, for instance, what does it use for state lookups? Integer arrays.