beginner array question

beginner array question

[lolo27]

hi
i am writing a generic package
generic
   ---------general parameters-----------
   type Someting is(<>);
   type something_array is Array (integer range<>) of Someting ;   

---------------------------------------------------
in the adb file i want to ask the following 
 function is_final(current_state:Someting ;final:something_array ) return boolean is
   begin
      if current_state in final'First..final'Last then
         return true;
      else
         return false;
      end if;  
   end is_final;
   
   ----

how can i ask if current_state is in final

thanks a lot

Re: beginner array question

[Jeff C,]

"lolo27" <limor_ru@walla.co.il> wrote in message
news:92bfc3dd.0311200234.2b74b41f@posting.google.com...
>  function is_final(current_state:Someting ;final:something_array ) return
boolean is
>    begin
>       if current_state in final'First..final'Last then
>          return true;
>       else
>          return false;
>       end if;
>    end is_final;
>
>    ----
>
> how can i ask if current_state is in final
>
> thanks a lot

Not like this at all.. The "in" keyword is not an array search operator.
There is no single "search" this array for
a value keyword. You need to look through your array checking each value in
the array to see if it is
= to the current_state value. If you find it, return true. If you make it
out of the loop without finding it, return
false.

Since I am (perhaps incorrectly) assuming this is a homework related issue,
I did not post code..Hopefully (either way) the text based info is enough to
get you on the right track.

Re: beginner array question

[David C. Hoos, Sr.]

You need to do it like this:

function is_final(current_state:Something ;final:something_array) return boolean is
  begin
     for i in final'range loop
        if current_state = final (i) then
           return true;
        end if;
     end loop
     return false;
  end is_final;

----- Original Message ----- 
From: "lolo27" <limor_ru@walla.co.il>
Newsgroups: comp.lang.ada
To: <comp.lang.ada@ada-france.org>
Sent: November 20, 2003 4:34 AM
Subject: beginner array question


> hi
> i am writing a generic package
> generic
>    ---------general parameters-----------
>    type Someting is(<>);
>    type something_array is Array (integer range<>) of Someting ;   
> 
> ---------------------------------------------------
> in the adb file i want to ask the following 
>  function is_final(current_state:Someting ;final:something_array ) return boolean is
>    begin
>       if current_state in final'First..final'Last then
>          return true;
>       else
>          return false;
>       end if;  
>    end is_final;
>    
>    ----
> 
> how can i ask if current_state is in final
> 
> thanks a lot
> _______________________________________________
> comp.lang.ada mailing list
> comp.lang.ada@ada-france.org
> http://www.ada-france.org/mailman/listinfo/comp.lang.ada
> 
> 

Re: beginner array question

[Jeffrey Carter]

lolo27 wrote:

> generic
>    ---------general parameters-----------
>    type Someting is(<>);
>    type something_array is Array (integer range<>) of Someting ;   
> 
> ---------------------------------------------------
> in the adb file i want to ask the following 
>  function is_final(current_state:Someting ;final:something_array )
 >  return boolean is
>    begin
>       if current_state in final'First..final'Last then
>          return true;
>       else
>          return false;
>       end if;  
>    end is_final;

There are a couple of problems here. "in" tests for subtype membership.
Final'First .. Final'Last (equivalent to Final'range) is a subtype of
Integer, because the index type of Something_Array is Integer. Within
the generic, Something is not an integer type, so this test should 
always return False.

Presumably you want to check if Current_State is equal to one of the
components of Final. To do that, you'll have to search Final. If Final
is sorted, you can use a binary search; otherwise, you'll have to use a
linear search.

Your construct indicates that you do not understand booleans. If you
could use the test you coded, you should have written

return Current_State in Final'range;

-- 
Jeff Carter
"I blow my nose on you."
Monty Python & the Holy Grail
03