Re: Beginer problem: variable array size

[tmoran@acm.org]

>The reality is that by putting a requirement out there that there must be no
>limit on the number of elements accepted, you create a difficulty that
>doesn't normally exist in the real world.
  I'd rephrase that as "you fudge away a difficulty that does exist in the
real world".  Obviously no program on a real computer will accept a truly
unlimited amount of input, and certainly not in a finite length of time.
It's just that by not explicitly dimensioning an array you make it seem as
if the input is umlimited.  If you use, for instance, a quadratic sort,
you're probably in fact limited to a few thousand elements before things
get totally unreasonable.  Given that input is coming from a user,
according to the problem statement, you might have 8*3600= 28800 values if
someone input one/second for 8 hours, so using
  List : array(1 .. 8*3600) of Integer;
and a better than quadratic sort is probably much simpler and more
reasonable than a (pretend) "no limit".  I think the prof's problem
statement should have ended with "Document and justify any assumptions
you had to make because of missing details in the problem statement."
  If the intent is to teach about linked lists and dynamic arrays,
a more realistic, and thus more convincing, problem with multiple
collections of various sizes, but a certain maximum sum of sizes,
would be better.