Subj : Re: largest memory block
To   : borland.public.cpp.borlandcpp
From : Mohsen
Date : Thu Mar 24 2005 01:32 am


>Have you determined that this is a problem in an application of yours,
>or are you afraid it may become one in the future?

It is a proplem for an application of mine right now. I have to
deal with huge arrays say of 1000000 elements or more. Using an
array of the following type makes the growing process slow:

TArray<TNode> Nodes(100, 0, 100);

Because, the application has to make 9999 reallocations to
accomodate 1000000 elements. Consider another example:

TArray<TNode> Nodes(100000, 0, 100000);

When reallocating, the occupied memory is 300000, because it
needs to keep the original array and also allocate a new block
of 200000 elements to deposit the previous array into it. And
if it cannot do that the program crashes.

>
>
>
>I don't understand this. What is less efficient than what here?

Comparing previous examples show what is less efficient than
the other. Reducing the array size and its growth delta
increases the number of reallocations, while reversing the
process reduces the number of reallocations and increases the
possibility of crashing. I think I could clarify what my
problem is. In my mind allocating the largest possible value
for the array size can be more efficent if we now the value in
advance.

Mohsen

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