Re: [DUG] O.o hmmm ok

Nick Wed, 06 Jun 2007 19:01:56 -0700

Right that makes sense :-)
So you could use a pointer then?


example

type
  TMyRec = Record
    name : string;
  end;

var
a : TMyRec;
b : ^TMyRec;
begin
a.name := 'Bob';

 b := @a;
 b.name := 'Smile';

 showmessage(a.name); //shows Smile



Judd, Struan (eCargo) wrote:

Records are constructs with Value semantics whereas Objects have
Reference semantics.

This means that in the following code is the Assignment 1 and Assignment
2 are semantically identical:

Var a, b: record
        name: String;
        age: Integer;
        end;

Begin
        a.name := 'Me';
        a.age := 39;

//      Assignment 1
        b := a;

//      Assignment 2
        b.name := a.name;
        b.age := a.age;
End;

TTFN, Struan.

Nick wrote:

Got something weird here - weird because I probably don't understand
it properly but it caused me a bit of delay... Simplified, I had a
global array of records, during my procedure I would do something

like this

PRec := MyArrayofPRec[0];
PRec.name := 'Hi';

Now for some reason I was expecting MyArrayOfPRec[0].name to be now

'Hi'as well, but it's not.


Here is an example that I whipped up just now which lead me to expect

this.

type
  TMyRec = Record
    name : string;
  end;


var
  Form1: TForm1;
  TTH : TMyRec;

procedure TForm1.FormCreate(Sender: TObject); begin
  TTH.name := 'BoB';
end;

procedure TForm1.Button1Click(Sender: TObject); var
  t : TMemo;
  b : TMyRec;
begin
  t := Memo1;
  t.lines.add('hi');

  b := TTH;
  b.name := 'Smile';
  t.lines.add(TTH.name);
end;

Now in this example when it's ran and button 1 is clicked - Hi is

added to the Memo1 and Bob is added.So why can I assign Memo1 to T and all actions done to T are done toMemo1, but the same isn't with the Record.Is it because Record isn't from TObject?

I guess it's like
var
    a,b : integer;
begin
    a := 1;
    b := a;
    b := 10; //a still = 1 which is what I would expect end;

so is it because TMemo is an Object and the record and a,b above are

just variables?

O.o
Thanks



_______________________________________________
NZ Borland Developers Group - Delphi mailing list
Post: delphi@delphi.org.nz
Admin: http://delphi.org.nz/mailman/listinfo/delphi
Unsubscribe: send an email to [EMAIL PROTECTED] with

Subject: unsubscribe

DISCLAIMER: This electronic message together with any attachments isconfidential. If you are not the intended recipient, do not copy, disclose oruse the contents in any way. Please also advise us by return e-mail that youhave received the message and then please destroy. Carter Holt Harvey is notresponsible for any changes made to this message and / or any attachments aftersending by Carter Holt Harvey. We use virus scanning software but exclude allliability for viruses or anything similar in this email or any attachment.


_______________________________________________
NZ Borland Developers Group - Delphi mailing list
Post: delphi@delphi.org.nz
Admin: http://delphi.org.nz/mailman/listinfo/delphi
Unsubscribe: send an email to [EMAIL PROTECTED] with Subject: unsubscribe

_______________________________________________
NZ Borland Developers Group - Delphi mailing list
Post: delphi@delphi.org.nz
Admin: http://delphi.org.nz/mailman/listinfo/delphi
Unsubscribe: send an email to [EMAIL PROTECTED] with Subject: unsubscribe

Re: [DUG] O.o hmmm ok

Reply via email to