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Why do arrays start at 0?

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Re: Why do arrays start at 0?

#251

Post by levodelellis »

bregma wrote: post #168

If you ask people which floor of building they're on, it's going to depend on which country they're in. In North America, at least, the first floor you walk into (in a sane city: I understand there are some which do not qualify in this respect due to hills or historic disaster recovery) is the first floor. On other continents, you enter the ground floor and need to take stairs or an elevating device to get to the fir…

I call `array[0]` the first element. I don't know what you'll think of that.

I wonder how many multiples of people who like arguing about starting from 1 vs 0 and how many people were confused for more than a day

Re: Why do arrays start at 0?

#252

Post by lupire »

atwood22 wrote: post #145
kazinator wrote: post #55

Earlier quoted context omitted.

What do you do for a living, and why are they paying you not to understand this?

Do you know the definition of countable? A set S is countable if there is a one-to-one mapping from S to N where N is the natural numbers. Do you know that 0 is not a member of the natural numbers? We literally start counting at 1 by definition of countable.

Nope.

Is the empty set countable? (Yes.)

Dictionary:

nat·u·ral num·bers

  the positive integers (whole numbers) 1, 2, 3, etc., and sometimes zero as well
Countable: https://en.wikipedia.org/wiki/Countable_set

Set theory:

https://en.wikipedia.org/wiki/Ordinal_number

Re: Why do arrays start at 0?

#254

Post by labrador »

Because zero is a concept that can mean "at the beginning"

The symbol changed over time as positional notation (for which zero was crucial), made its way to the Babylonian empire and from there to India, via the Greeks (in whose own culture zero made a late and only occasional appearance; the Romans had no trace of it at all)

Another meaning is "nothing" but we're talking about position, not nothingness

The mathematical zero and the philosophical notion of nothingness are related but are not the same. Nothingness plays a central role very early on in Indian thought (there called sunya), and we find speculation in virtually all cosmogonical myths about what must have preceded the world's creation. So in the Bible's book of Genesis (1:2): "And the earth was without form, and void."

https://www.scientificamerican.com/article/what-is-the-origi...

Re: Why do arrays start at 0?

#255

Post by systemvoltage »

bregma wrote: post #168

If you ask people which floor of building they're on, it's going to depend on which country they're in. In North America, at least, the first floor you walk into (in a sane city: I understand there are some which do not qualify in this respect due to hills or historic disaster recovery) is the first floor. On other continents, you enter the ground floor and need to take stairs or an elevating device to get to the fir…

I've been living in North America for decades. Every building has G (zero). This is the floor that you walk into and has a lobby. The next floor up is 1 as such is labeled in the elevator.

So your initial assumption is incorrect from my experience.

Re: Why do arrays start at 0?

#256

Post by lupire »

goatlover wrote: post #150
kazinator wrote: post #58

Earlier quoted context omitted.

The counting activity doesn't begin when the first item is registered; it begins when the counter is initialized to zero. A decision is made to begin counting, along with the realization that nothing has been counting yet. That's when counting has started. When the first item is seen, the counting is then continuing. Suppose your job is to count some events. You check in for work at 8:00 a.m., but the first event has…

What counter? You're saying a counter exists before people start counting? Is this a form of mathematical Platonism?

What does your stopwatch say right now?

Your pedometer?

Your traffic clicker?

Re: Why do arrays start at 0?

#257

Post by lupire »

rcoveson wrote: post #61
atwood22 wrote: post #25

Earlier quoted context omitted.

No, birthdays are 1 indexed. Your Nth birthday is the day you turn N years old. When you're 1 year old, you've been alive for 1 year, not 2 years.

No, old calendar systems are one indexed. In those system, there is literally no year zero; the first year is year one. This leads to crazy things like year 100 being part of the "first century" and year 101 being part of the "second century". That is not the case with age or birthdays which are, thankfully, zero indexed. The first year of human life is age=0, birthdays=0.

It's not "crazy". No one care about which century X00 is. The term "century" doesn't have enough sig figs. X00 is "the turn of the century".

Re: Why do arrays start at 0?

#258

Post by [deleted] »

rcoveson wrote: post #61
atwood22 wrote: post #25

Earlier quoted context omitted.

No, birthdays are 1 indexed. Your Nth birthday is the day you turn N years old. When you're 1 year old, you've been alive for 1 year, not 2 years.

No, old calendar systems are one indexed. In those system, there is literally no year zero; the first year is year one. This leads to crazy things like year 100 being part of the "first century" and year 101 being part of the "second century". That is not the case with age or birthdays which are, thankfully, zero indexed. The first year of human life is age=0, birthdays=0.

[deleted]

Re: Why do arrays start at 0?

#259

Post by lupire »

pb7 wrote: post #97
lupire wrote: post #94

Earlier quoted context omitted.

"ordinal" is preferred to "index", as "index" doesn't naturally suggest starting at "1", or even restricting the key to integers. "Ordinal" starts from 1, everyone agrees (except mathematicians, of course :-) ).

Ask 100 random people on the street and I'd be surprised if even 1 knew the definition of "ordinal". It's an uncommon word.

So is "array". What's your point? My point is that it is unambiguous once you say what you are talking about.
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