raised CONSTRAINT_ERROR

[Matthias Teege <matthias@mteege.de>]

Moin,

I made my first steps in Ada using GNATS under FreeBSD and
now I have a problem that I didnt understand. The followig
code gives me a raised CONSTRAINT_ERROR (in Line:
StrArg := Ada.Command_Line.Argument(I)) and I didnt know
why.

with Ada.Command_Line; use Ada.Command_Line;
with GNAT.IO; use GNAT.IO;

procedure Cldemo is

Argcount: Natural;
StrArg : String (1 .. 10);
I: Positive := 1;

begin
   Argcount := Ada.Command_Line.Argument_Count;

Schleife:
   while I <= Argcount loop
      StrArg := Ada.Command_Line.Argument(I);
      Put_Line(StrArg);
      I := I + 1;
   end loop Schleife;

end Cldemo;

If I change the Code to

with Ada.Command_Line; use Ada.Command_Line;
with GNAT.IO; use GNAT.IO;

procedure Cldemo is

Argcount: Natural;
I: Positive := 1;

begin
   Argcount := Ada.Command_Line.Argument_Count;

Schleife:
   while I <= Argcount loop
      Put_Line(Ada.Command_Line.Argument(I));
      I := I + 1;
   end loop Schleife;

end Cldemo;

all works perfect. What is the main difference between
both versions?

Thanks for any hints
Matthias