Re: Concatenation and Characters

[Preben Randhol <randhol+news@pvv.org>]

Justin Birtwell wrote:
> This is what I don't understand!  How can you declare a string variable when
> you don't know before hand what the string is going to be?  Do you overload
> the String like String(1..80) and hope for the best?  This seems like
> overkill.  I know this must really be boner of a newbie question, but I'm
> baffled.

Relax :-)

The point is that Ada is a strict language. It does boundary checks etc
and to do this it needs to know the size of the string. But you also
have variable strings. Let me first show you an example:

with Ada.Strings.Unbounded;
use  Ada.Strings.Unbounded;
procedure string_test is

   First_Name : String (1 .. 6) := "Preben";
   Sirname    : String (1 .. 7) := "Randhol";

   -- Defining a String with fixed length
   Full_Name : String (1 .. 14);

   Variable  : Unbounded_String;
begin
   
   Full_Name := First_Name & " " & Sirname;

   -- Another way

   declare
      Name : String := First_Name & " " & Sirname;
   begin
      -- You can now use Name here. You don't have to say that 
      -- it is 1 .. 14 because it will be defined as you use the :=
   end;

   -- Another way using Unbounded string:

   Variable := To_Unbounded (First_Name & " ");  
   Variable := Variable & To_Unbounded (Sirname);

   --  You see that you can now have a variable length string and
   --  Add parts as you like.

end string_test;

> 
> I look forward to you your response,
> Justin
> 
> 


-- 
Ada95 is good for you.
http://libre.act-europe.fr/Software_Matters/02-C_pitfalls.pdf