Hello,

I would like to verify if a string is a valid number, as in StrToInt will work when applied to it. The obvious way is making a try statement:

      try
        StrToInt(TokenStr);
        AdicionarToken(tNumeroLiteral, TokenStr);
      except
        AdicionarToken(tId, TokenStr);
      end;

but I don't like this solution, because a lot of exceptions will be caused by normal execution of my program, which will disturb debugging it ...

It's easy to build such a routine, but I was just thinking that maybe there is one already somewhere in the RTL or FCL ... anyone know?

thanks,

Have a Original Message -----

Hi!

Am Sonntag, den 23.11.2008, 14:18 -0200 schrieb Felipe Monteiro de Carvalho:

Always avoid exceptions if possible, since they are very costly in terms CPU time. Do your error handling with exceptions, but not routine tests. This would be misuse of exceptions.

For your problem just use the original Pascal procedure Val(St:String;Var Value,Position:Integer)
which simply returns the position of an illegal character or 0 if the string was a legal number.

Bye
Hansi

If TryStrToInt(s,i) then
  Writeln('S has a valid number:',I);

Or

  Val(S,I,C);
  If C=0 then
   Writeln('S has a valid number:',I);

Michael.

Johann Glaser wrote

Always avoid exceptions if possible, since they are very costly in terms CPU time.

I know this was the rule of thumb in Delphi 5-7 days... Does this still apply today, with newer compilers and much faster CPU's? Just curious...

Regards,
- Graeme -

_______________________________________________
fpGUI - a cross-platform Free Pascal GUI toolkit
http://opensoft.homeip.net/fpgui/

Yes. The code must save all registers, set a jump point etc. Quite costly.

Michael.

thanks, Val worked nicely =)