[fpc-pascal] Arrays of objects

Joao Morais post at joaomorais.com.br
Wed Oct 31 12:10:28 CET 2007

Adrian Maier wrote:
> On 10/31/07, Matt Emson <memsom at interalpha.co.uk> wrote:
>> Adrian Maier wrote:
>>> Hello,
>>> I'm seeking for advice about which is the best way to hold an array of
>>> class instances
>>> I need to access the elements using its position (like a regular
>>> array) , and also i'd like
>>> the structure to grow when I add more elements
>> TObjectList
> I am aware that TObjectList is one of the possible ways.
> But I was hoping to get a better understanding about the purpose of these
> various classes or types of array ,  and more importantly what are the
> drawbacks .
> Is there really no wiki page , tutorial, anything  that provides an overview of
> the collections and types of arrays that FPC has ?

You can use dynamic arrays, they work like an ansi string:

   VArray: array of TSomeClass;
   SetLength(VArray, 10);
   // now you have VArray[0] .. VArray[9];
   SetLength(VArray, 20);
   // now you have [0] .. [19];
   // Length(VArray) = 20
   // for I := 0 to Pred(Length(VArray)) is a valid statement

They are reference counted, just like ansi strings, ie don't worry about 
memory leakages.

Joao Morais

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