Re: unsigned type

[Rob Solomon <usenet@drrob1-noreply.com>]

I was able to use the Natural and Positive.  

Now I'm trying to understand Mod types.

I tried this:
type card31 is mod 2_147_483_648;
type card32 is mod 4_294_967_296;
c31 : Card31;
c32: Card32;
LI : Long_Integer;
and

LI := Long_Integer(c32);

How to I output c31 and c32?  Modula-2 uses WriteCard or CardToString
and WriteString

I tried using Put, but I got an error saying that correct procedure
could not be found, or something like that.

Put(LI) works until the value of LI > 2**31, even for c32.

Thanks for helping
--rob

On Sun, 28 Jun 2009 19:54:28 +0000 (UTC), tmoran@acm.org wrote:

>>I am trying to declare a type as unsigned using Ubuntu 9.04 GNAT
>>compiler.  I know Ada does not have a type CARDINAL, but I thought it
>>had a type Unsigned.
>
>Ada's equivalent is Natural.  If
>  Lowest : Natural := 0;
>  Highest : Natural := Natural'last;
>then
>  Lowest  := Lowest-1;  -- will raise an exception
>  Highest := Highest+1; -- ditto
>
>(Note that Gnat by default is not a legal Ada compiler because it doesn't
>check for and raise the exception.  You need a command line parameter
>-gnato to make it act like Ada.)
>
>The standard Ada package Interfaces has hardware-oriented types
>Unsigned_8, Unsigned_16, etc but those are modular types so if
>  Empty_Word : Interfaces.Unsigned_16 := 0;
>  Full_Byte  : Interfaces.Unsigned_8 := 255;
>then
>  Empty_Word-1 will be 65535.
>  Full_Byte+1 will be 0.
>with no exceptions raised.
>
>You can also declare your own application oriented non-negative types
>  type Ratings is range 1 .. 10;
>or modular types
>  type Degrees is mod 360;  -- 0 .. 359 wrapping around