I'm in the middle of a java code quiz and was wondering if anyone knows whats an "off-by-one" error when using arrays.

i'm taking a wild guess - your program is going beyond the size of an array, thinking it's 1 unit bigger than it really is.


yep, http://www.cs.ucl.ac.uk/staff/t.pag...javaErrors.html


p.s. you sneaky bastard

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Hmmm... If you exceed the set length of an array in Java you should be getting a 'NullPointerException'.

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quote:

Originally posted by whiskers i'm taking a wild guess - your program is going beyond the size of an array, thinking it's 1 unit bigger than it really is. yep, http://www.cs.ucl.ac.uk/staff/t.pag...javaErrors.html p.s. you sneaky bastard

ahahaha thanks whiskers

quote:

Originally posted by whiskers i'm taking a wild guess - your program is going beyond the size of an array, thinking it's 1 unit bigger than it really is.

Yeah, java starts counting at 0 when indexing arrays, which also means that the last element is (size-1).

It's another thing java got from C/C++: in C a[i] is equivalent to *(a+i). 'a' decays to a pointer which points to the first element in the array (i.e. the first element is *(a+0) or a[0]).

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quote:

Originally posted by Fundamental Hmmm... If you exceed the set length of an array in Java you should be getting a 'NullPointerException'.

Yeah the nullexception would work, but the question i was asked was asking the about anatomy of an off-by-one error.




And they are not letting me use a compiler!