Need some Help with Dynamic Arrays

[OveRride]

Well, I've been programming in most basic environments, VBasic 4/5/6... Delphi 5... and now I'm approaching MSVC++ and I'm facing some troubles understanding arrays...

well, let's get to the point, in most languages, for example in vb, I could declare an array without specifying the exact size, and then use Redim ArrayName(newsizes) to redim it. Optionally I could use the Preserve keyword to avoid clearing the array after redim.

How do I make a redim-able array in MSVC++ ???

this code

int myint[];

produces a error C2133: 'mod' : unknown size

also, If I use it in a class interface definition, it does not produce errors, but just a warning

warning C4200: nonstandard extension used : zero-sized array in struct/union

So I've been looking in the help and some other guides, and I have the feeling that a possible solution would be using malloc, or the "new" operator... but since I got my mind messed up with that stuff, I'll wait for you Gurus to tell me your opinion.

Thanx in Advance.

 

[TheInsider]

Hi,
I once majored in C/C++, but have not programmed in it for ages - so I am rusty. I'll take my chances at being wrong here... the only real dynamic array that can be created in C/C++ is a character string. To overcome this you must use a linked list, this is where you would use the "new" operator.

Rob Marriott
rob@career-connections.net

 

[palbano]

Dear OveRride,

Yes, you are one the right track...

int* pint = NULL;
pint = new int[20];

or..

int nCount = 20;
pint = new int[nCount];

don't forget to clean up

delete pint;

> Optionally I could use the Preserve keyword to avoid clearing the array after redim.

Now that is a little different. That's where classes come into play. A C++ class can be designed to encapsulate the concept of a 'redim-able' array and hide all the details of memory allocation and copying values to grow the size of the array.

Hope this helps
-pete

 

[Pappy1942]

Hi,

I've not done any c++ programing for awhile but I seem to remember that the line

delete pint;

should be

delete []pint;

I KNOW from past blunders that these little things can cause a lot of problems.

Dick

 

[palbano]

Dear Pappy1942,

That would be true if the elements of the array were objects so that their destructors would be called.

-pete