Re: Simple program to find average of 3 numbers

[Robert A Duff <bobduff@shell01.TheWorld.com>]

mheaney@on2.com (Matthew Heaney) writes:

> But the question is: what is the base range of the "implementation
> defined integer type"?  For declarations of this style:
> 
>    type T is new Integer range 1 .. 100;
> 
> can was assume that the base range of the type includes all the values
> in Integer'Base,

Yes.

>... or only the values in the range -100 .. 100?
> 
> With respect to the base range of the type, how do the declarations
> 
>    type T is new Integer range 1 .. 100;

Base range is at least Integer'First..Integer'Last,
which is at least the 16-bit range.

>    type T is range 1 .. 100;

Base range is at least -100..100.

> differ from one another?

The above is according to the RM.  These are minimal ranges.  Compilers
can choose wider base ranges, and for any particular expression, the
compiler is always allowed to get the right answer even if it is outside
the base range.  Base ranges give you a minimal range for intermediate
results, guaranteed not to overflow.

- Bob