Re: integer'image

[Ted Dennison <dennison@telepath.com>]

In article <29IK4.5459$sB3.3596@news.indigo.ie>,
  "NANCY HEHIR" <nanceh.ennis@tinet.ie> wrote:
> for x in 1..20 loop
>     integer_string:=integer'image(x);
> end loop;
>
> everything is fine until x=10. This raises a constraint error which I
> interpret to be a problem with mismatched string lenghts. If I

> I'm sure that it is a standard application to convert integers to
> their string images but I can't figure what I'm missing here.

The problem isn't your integer-string conversion idiom, its your string
assignment idiom. You can't expect to be able to assign a varying-length
string into a fixed length string. It'll only work if the lengths of the
two strings just happen to be equal.

There are several ways to save your string image. One is to initialize a
constant (or variable) with the string itself, eg:

   for x in 1..20 loop
      declare
         Integer_String : constant String := Integer'image(x);
      begin
         ...
      end;
   end loop;

Another way would be to declare a string big enough to hold the largest
value you'll get, and keep track of its length:

   for x in 1..20 loop
      Integer_String_Length := String'length(Integer'image(x));
      Integer_String(1..Integer_String_Length) := Integer'image(x);
   end loop;


Another would be to use either Ada.Strings.Unbounded.Unbounded_String or
Ada.Strings.Bounded.Bounded_String.

--
T.E.D.

http://www.telepath.com/~dennison/Ted/TED.html


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