[fpc-pascal] Succ() and Pred() operations

[Ricardo Viégas]

Hi there!

I have installed FPC 2.2.0 [2007/09/09] a few days ago on my WinXP-Pro-SP2, and I'm just taking a Web Tutorial on the language.
when I come to "User defined variable types", I decided to make the following test:

Program Test (Output);
Type Vars = (var0, var1);
Var x : Vars;
Begin
   x := var1;
   x := Succ (x);
   Writeln ( Ord(x) );
   x := var0;
   x := Pred (x);
   Writeln ( Ord(x) );  
   End.

It compiled and executed without error, and returned following 2 lines:
2
-1

Is that supposed to be the correct output, or should it have pointed an error during execution?
The first symbol of the set has value "0", and second one, value "1". To which symbols corresponds the values "2" and "-1"?

Since this is my first posting, I could be on the wrong list. If that is the case, please let me know.
Thanks in advance.
Best regards, Ricardo

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Ricardo Viégas
São Paulo - SP - Brasil