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LesHurley LesHurley is offline
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Default array dimensioning

ilia; sory for the long delay in answering your question. In C/C++ you
create dynamic arrays and change their dimensions using the malloc() function
to create and expand and the free() function to release previously allocated
memory. Such a capability is essential in database programs where arrays of
large user defined class objects are the normal. Ordinarily no one knows in
advance how many iems the array will hold or how much memory will be
required, thus the need for dynamic allocation. It's been 5 or 6 years since
I did any C++ programming and I had to go back and look it up. HTH.
--
Thanks for your help


"ilia" wrote:

Just curiosity - how in C++ do you increase/decrease the dimension of
an array? C++ doesn't even know what an array is, from what I
understand.


On Mar 15, 12:23 pm, LesHurley
wrote:
Thanks everyone
--

"Alan Beban" wrote:
Rick Rothstein (MVP - VB) wrote:
Then you missed the part where Chip wrote about the Preserve keyword.


You can ReDim the array as often as you want. ReDim will cause the
existing
contents of the array to be lost unless you use the Preserve modifier.


ReDim Preserve Arr(0 To 11)


Rick


A bit more needs to be said.


If Arr is a true variant() type array [e.g.,
Dim Arr()
ReDim Arr(1 to 10, 1 to 2)]
then with the Preserve keyword you can change only the upper bound of
the last dimension
[e.g.,
Dim Arr()
Redim Arr(1 to 10, 1 to 2)
ReDim Preserve Arr(1 to 10, 1 to 4)]
In this case, if you try to change either bound of the 1st dimension, or
the lower bound of the 2nd dimension, you will get a Subscript out of
range error.


If, however, Arr is a an array contained within a Variant type variable
[e.g.,
Dim Arr
Redim Arr(1 to 10, 1 to 2)]
then with the Preserve keyword you can change either or both bounds of
the last dimension [e.g.,
Dim Arr
Redim Arr(1 to 10, 1 to 2)
ReDim Preserve Arr(1 to 10, 0 to 3)]


If the functions in the freely downloadable file at
http:/home.pacbell.net/beban are available to your workbook, then you
can use the ResizeArray function to preserve the values of the array
that is passed to it and change the lower and/or upper bounds of any or
all of the dimensions of a one-, two- three- or four-dimensional
array, or increase (up to 4) or decrease the number of the array's
dimensions (whether or not the array is contained within a Variant type
variable).


Alan Beban