Re: Converting Type Characters to type string

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Mon, 31 Mar 2008 07:44:52 -0700 (PDT), jedivaughn wrote:

> Ok, Let me start over. Maybe I'm not approaching my problem the right
> way. I'm trying to write a program that converts integers to roman
> numerals or vice versa depending on the user input. to do this I
> thought I would get the input in separate characters so that I can
> easily compare the values to find whether the user inputed IX or XI or
> something else. This works until unless the user wants to convert an
> integer to roman numeral. to change the input to an integer I'm using
> this int:=Integer'Value(str); But for this to work the input has to be
> in a string not a character. I thought about taking the input as a
> string and then doing a string slice on the characters and storing
> them in different variables but once again I'm not sure how many
> characters will be entered so how can I do that? So how would be the
> optimal way of going about this?

Sorry, I still do not understand the problem. You read a line. Then you
skip spaces there. Then you try to parse an integer number starting from
that position. If that fails you try to parse a Roman number. After
successful parsing you advance to the position following the number and
skip spaces again. Then you check if the whole like was matched. That's it.

Here is a complete program:
--------------------------
with Ada.Text_IO;              use Ada.Text_IO;
with Strings_Edit.Integers;    use Strings_Edit.Integers;
with Strings_Edit.Roman_Edit;  use Strings_Edit.Roman_Edit;

procedure Arabic_Roman_Converter is
begin
   loop
      Put_Line ("Enter a number:");
      declare
         Input  : constant String := Get_Line;
         Number : Integer;
      begin
         exit when Input'Length = 0;
         begin
            Number := Value (Input);
            Put_Line ("You typed " & Image (Roman (Number)));
         exception
            when End_Error =>
               -- OK, no integer here, maybe it is a Roman number?
               Number := Integer (Roman'(Value (Input)));
               Put_Line ("You typed " & Image (Number));
         end;
      exception
         when Data_Error =>
            Put_Line ("Bad input, possibly syntax or several numbers");
         when Constraint_Error =>
            Put_Line ("The number is too large");
         when End_Error =>
            Put_Line ("No any number found");
      end;
   end loop;
end Arabic_Roman_Converter;   
-----------------------------------
Enter a number:
 II
You typed 2
Enter a number:
3
You typed III
Enter a number:
1000
You typed M
Enter a number:
f
No any number found
Enter a number:


-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de