How can I reserve memory for pointer to an array in Delphi?

I'm developing class to represent special kind of matrix:

  DifRecord = record
    Field: String;
    Number: Byte;
    Value: smallint;

  TData = array of array of MainModule.DataRecord;

  TDifference = array of DifRecord;

  TFogelMatrix = class
    M: Byte;
    N: Byte;
    Data: ^TData;
    DifVector: ^TDifference;
    procedure init(); 
    constructor Create(Rows, Cols: Byte);
    destructor Destroy;

Now in constructor I need to reserve memory for Data and DifVector class members. I use pointers to array of records, as you see. So, the main question is, how can I correctly reserve memory? I suppose I can not use something like that: new(Data); new(DifVector); cause I`m loosing the main idea - to reserve memory space, as much as I want to, at run-time. Thanks for comments.


Since you're using dynamic arrays, array of, then you should use SetLength to specify the length of the array, which can be done dynamically.

ie. like this:

SetLength(Data, 100);

This will not reserve 100 bytes, but will reserve enough space to hold 100 elements of whatever type the array holds.

Change your declarations for the arrays to simple arrays:

Data: TData;
DifVector: TDifference;

and use it with SetLength, it should do the trick.

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