> The usual arguments involving pointer arithmetic Yeah, I think this exactly why it is zero based. The index became a simple multiplier for sizeof(int).
An assembler spillover into C.
Why do arrays start at 0?
21–30 of 702 posts
Re: Why do arrays start at 0?
#22I'm fine with 0-based, 1-based or anything-based arrays (I recall it being convenient solving 8queen with pascal), but for Rage-Over-A-Lost-Penny sake, music note intervals are always beyond my understanding.
Same pitched notes are called "interval 1" and there goes thirds, fifths, sevenths... All off-by-one in my base-offset-addressing mind... And then major vs. minor which creates all kinds of "aliased addresses"...
I'd really love a BASE-12 floating number representation. Like 4.00 for the middle C; Chords can be then represented by a tuple of such numbers -- major = [+0.04, +0.07] (some sequencers already do something like that and I'm far better at reading that kind of sequencer data than a sheet)
Re: Why do arrays start at 0?
#23Arrays start at 0 because they're really just pointers. "[x]" is just shorthand for "+ x * sizeof". The first element is the one stored at the pointer address (0 sizeofs ahead of the pointer, the next element is stored 1 sizeof ahead of the pointer, etc.
In C, "a[x]" is effectively syntactic sugar for just "*(a+x)" (conversion rules for "+" means you don't need the sizeof). It also means you can reverse it and write e.g. "5[somearray]" if you really want to make developers want to throw rocks at you.
Re: Why do arrays start at 0?
#24Arrays start at 0 because they're really just pointers. "[x]" is just shorthand for "+ x * sizeof". The first element is the one stored at the pointer address (0 sizeofs ahead of the pointer, the next element is stored 1 sizeof ahead of the pointer, etc.
That's just convention though. There's no reason "[x]" couldn't have been defined to be "+ (x - 1) * sizeof". There would be no runtime cost to this, and the compile time penalty would be tiny even on ancient systems.
Re: Why do arrays start at 0?
#25It really comes down to a choice between a machine-focused (0) or human-focused (1) approach. The 0 makes a lot of sense in a C pointer world where memcpy and other alike functions can be written very thight. The 1 makes a lot of sense in a human world, when we count, we start at 1, we talk about the "1st", counting on finger starts with 1, etc. I once were at a Lua (1 indexed language) conference where this was disc…
> when we count, we start at 1, we talk about the "1st" Although often with an implicit zero. Under typical North American culture, your 1st birthday, for example, is more accurately the first anniversary of your birthday. Your birth is zero indexed.
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.
Re: Why do arrays start at 0?
#26It really comes down to a choice between a machine-focused (0) or human-focused (1) approach. The 0 makes a lot of sense in a C pointer world where memcpy and other alike functions can be written very thight. The 1 makes a lot of sense in a human world, when we count, we start at 1, we talk about the "1st", counting on finger starts with 1, etc. I once were at a Lua (1 indexed language) conference where this was disc…
If you think of the index as an offset you would start with 0.
BTW on which level is the 1st floor?
Re: Why do arrays start at 0?
#27Edsger Dijkstra wrote an interesting article titled 'why numbering should start at 0'.
Perhaps not answering the question directly but an interesting read nonetheless.
https://www.cs.utexas.edu/users/EWD/transcriptions/EWD08xx/E...
Re: Why do arrays start at 0?
#28It really comes down to a choice between a machine-focused (0) or human-focused (1) approach. The 0 makes a lot of sense in a C pointer world where memcpy and other alike functions can be written very thight. The 1 makes a lot of sense in a human world, when we count, we start at 1, we talk about the "1st", counting on finger starts with 1, etc. I once were at a Lua (1 indexed language) conference where this was disc…
> when we count, we start at 1, we talk about the "1st" Although often with an implicit zero. Under typical North American culture, your 1st birthday, for example, is more accurately the first anniversary of your birthday. Your birth is zero indexed.
Yeah age is confusing even for non-computer-folks :)
If you have 4 classes in school today, you would never talk about the 1st class as number 0, the last one is the 4th, not the 3rd.
Re: Why do arrays start at 0?
#29Earlier quoted context omitted.
> when we count, we start at 1, we talk about the "1st" Although often with an implicit zero. Under typical North American culture, your 1st birthday, for example, is more accurately the first anniversary of your birthday. Your birth is zero indexed.
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.
The moment you are born you are 0 years old (or perhaps 0.75 years old, but we don't usually recognize that). We count from zero in this case, at least implicitly.
In some cultures you are considered 1 the moment you are born, so the zero indexing isn't universal here, but typical in North America as noted earlier.
Re: Why do arrays start at 0?
#30It really comes down to a choice between a machine-focused (0) or human-focused (1) approach. The 0 makes a lot of sense in a C pointer world where memcpy and other alike functions can be written very thight. The 1 makes a lot of sense in a human world, when we count, we start at 1, we talk about the "1st", counting on finger starts with 1, etc. I once were at a Lua (1 indexed language) conference where this was disc…
If you think of the index as an offset you would start with 0. BTW on which level is the 1st floor?
> BTW on which level is the 1st floor?
in Europe or in the US?