I'd suggest looking again at DeMorgan's Law of boolean expressions. I've 
made this mistake dozens of times over the years.

                                 Randy.

"Mehdi Saada" <00120260a@gmail.com> wrote in message 
news:fd7c28a6-5605-4521-b9e9-f88b47b9714d@googlegroups.com...
This piece shall verify the program's arguments. I don't understand why 
whatever the first argument is, it doesn't raise EXC_COMMANDE as expected.
It should do it if ARGUMENT(1)(1) isn't 'n','c','N','C'.

      if Argument_Count /= 2 then PUT_LINE ("Pas le bon nombre 
d'arguments."); raise Exc_Commande;
      elsif Argument (1)'Length /= 1 and ARGUMENT(1)(1) not in 'n'| 'c'| 'N' 
| 'C' then
        PUT_LINE ("Première argument incorrect: veuillez mettre un (seul) 
charactère entre n, c, N et C."); raise Exc_Commande;
      elsif ADA.Strings.Fixed.Index (Argument (2), Alphanumeric_Set, 
Outside) /= 0 then
  PUT_LINE ("Deuxième argument incorrect: l'acronyme ne peut pas contenir de 
chiffres !"); raise Exc_Commande;
      end if;