You could declare the array as array[0..100] of something resp. array[1..100] of something for 0/1 based, and just as well do array[2..100] of something, or array[-1..100] of something, for -1/2 based.
Or with letters array['a'..'z'] of something,
Or with enums. TEnum = (red, blue, green), and then an array array[red..green] of something
Actually, that is just Pascal