In this example, people also call the floor with index 1 the "first floor," although they don't call the ground floor the zeroth floor, as you say.
Since floors can go below ground, the first underground floor is floor -1, so everything works out. There's a floor for every number, unlike with 1-based floor numbering, where floors go from -1 to 1.
By the way, has anyone else had this problem: you're on floor 10, say, and you want to get to floor 15, say, so you run up 5 flights of stairs and try to find the room but then after a while you realise that somehow you've ended up on floor 16 so you think you're going demented and can't count but after this has happened a few times you realise ... THE IDIOTS HAVE OMITTED FLOOR 13!
If there's one thing worse than 1-based indexing it's leaving-out-13-based indexing ... Has any programming language tried doing that with arrays, I wonder?
I see what you did there.
Somebody should create a programming language that implements all real-world number idiosyncracies. Don't have 4 or 13; define π as 3 and τ as 6, print 6 three times every time it occurs for good luck (or bad luck, depending on where you live), replace all numbers close to 8 with 8 in money values for great prosperity, have a constant for "dozen" that's 13 in case you're counting loaves of bread, have a rounding function that rounds to a close number that's easy to say depending on your locale...
And let's go with 0.5-based indexing as a compromise.
