"SIGSEGV" error : How do I do OOP correctly?

[I_am_root]

I'm new to FP even if I programmed in Basic and BP before.

I tried some stuff like this :

[pascal]
Unit MyUnit;

{$MODE DELPHI}


INTERFACE

uses classes;

Type TMyObj = class
Public
a : Integer;
End;

IMPLEMENTATION

End.
[/pascal]

...and the test program...

[pascal]

Program MyBuggyProgram;
{$MODE DELPHI}
uses classes, crt;

Var
MyObj : TMyObj;

Begin

clrscr;
Write(MyObj.a); // SIGSEGV
Readkey;

End.


[/pascal]

You'll get SIGSEGV. How do I do this correctly?

Thx in advance.

________________
Regards,
Eduard

[dmantione]

You didn't create any object, so variable myobj is undefined. Create one first.

[Clootie]

Does FPC support "object" style (old TurboPascal) classes?

[dmantione]

Of course it does Just use "object" instead of "class", and the compiler will know what to do with it.

[I_am_root]

Many thanks, dmantione . It works perfectly now.



_________________
Regards,
Eduard

[WILL]

Here are a few tutorials that I recommend giving a read. Object Pascal is a different animal from Pascal. The main thing is the concept of Objects and structures in your code. Once you learn this though, you'll love 'em. It even makes some of your code much more powerful and easier to impliment stuff once done right. It just takes some time to get used to the concept of OOP.

Object Oriented Programming in Delphi - A Guide for Beginners
Essential Pascal

There is more material in the PGD Library, you are more than welcome to visit and read through everything. Some other languages are available for some items, but it's mostly in english though.