Redim in c++

[Boomba]

Is it possible to redim field in c++ like Redim or Redim Preserve in VB?
I have a class with CString field but I dont know how many members I need for that field. (That depends and it is not allways same)

[Swatty]

I don't think you can do it in C++.

In VB there it is available but I think in the background VB creates a new array , and copy's the values allready in it.

I think you'd better provide the maximum space you could think is needed.

[Boomba]

Thanks Swatty,
I need it because I want to "save" RAM resources maximum is possible, and program will create objects only if they is needed.
I did it in VB, I think must be a some way to do that in C++

[Jop]

Maybe you could try the vector class.. that will allocate more space when needed...

[CornedBee]

Of course there is a way, but it's more than one command. Use a CStringArray that is native to MFC and you'll be fine.

[gearbolt]

you can use a pointer to create a dynamic array

[parksie]

If you don't understand pointers and memory management, don't use MFC.

Easiest way is a vector, like Jop says:

#include <iostream>
#include <vector>
#include <iterator>

using namespace std;

int main() {
        cout << "Please enter some numbers, end with -1: " << flush;

        vector<int> nums;
        int num = 0;

        while(!cin.eof()) {
                cin >> num;

                if(num == -1 || cin.fail()) {
                        // stop when we get either -1 or something
                        // that wasn't recognised as a number
                        break;
                }

                nums.push_back(num);
        }

        cout << endl << "You entered:" << endl;

        copy(nums.begin(), nums.end(), ostream_iterator<int>(cout, "\n"));

        cout << endl;

        return 0;
}

[CornedBee]

If I was already using MFC, I'd stay with their containers. The MFC containers are actually easy to use and don't have the confusing (for new people) iterators and such.

[parksie]

They do use iterators, after a fashion...at least from what I remember (with POS_TYPE and all that, or something...).

I just like the way that everything in the STL works so seamlessly, for example you can copy a vector to a list with one line

[CornedBee]

No they don't. The only thing: a linked list uses POSITION, which is just a disgused node pointer. I admit it doesn't offer as much functionality as the STL, but still... it's native to MFC (and supports serialization BTW, STL doesn't do that)

[parksie]

Originally posted by CornedBee
(and supports serialization BTW, STL doesn't do that)

True.

Although I doubt it would be too difficult to make some kind of generic operator>>/<< for an iterator range

[CornedBee]

I think it wouldn't be easy. MFC's serialization mechanism is quite complicated.
Well, you could probably override a function in the process and catch a specific byte sequence. Or you could create a dummy class that is created by the << iterator operator and serialized which in turn creates a STL object and fills it with the data when unserialized.
But it wouldn't be trivial.