Re: type declaration and storage requirements

["David Thompson" <david.thompson1@worldnet.att.net>]

Russ <18k11tm001@sneakemail.com> wrote :
> Ada allows me to specify the number of digits and the range of a
> floating-point type, or the delta and range of a fixed-point type.
> This gives more control than, say, C/C++, which only allows me to
> specify single or double precision. ...

C and C++ don't have fixed-point at all, although in C++
you could cobble up a perhaps-templated class (= ADT)
that does a tolerable approximation except for literals.

For floating-point, there's a more-or-less workaround:
#include <float.h>
...
#if FLT_DIG >= 11 /* single is good enough */
typedef float mytype;
#elif DBL_DIG >= 11 /* single isn't but double is */
typedef double mytype;
#elif LDBL_DIG >= 11 /* not double but 'extended' */
typedef long double mytype;
#else
#error We lose, no suitable floating type
#endif

In C++, you can also use std::numeric_traits<>,
but only at 'compile time' not in the preprocessor.
Which Ada-trained folks may prefer anyway <G>
except that it can't alter a function 'signature'
i.e. the choice of dummy/formal/parameter types.

And of course neither C nor C++ has user-set ranges
(or subtypes) distinct from the underlying/base type's range,
though again in C++ you could write a class to do it, but
only at runtime cost, since the uneuphoniously-named
'non-type template parameters' can't be floating-point.
Well, unless you (can) inline everything and the compiler
can determine/prove no aliasing, I think that works but
I'd have to try it out to be certain.

(Aside:  'C/C++' is even more flamebaitful in comp.lang.c
then 'ADA' is here.  C is _not_ strictly a subset of C++,
though it is _close_ by any reasonable measure.)

--
- David.Thompson 1 now at worldnet.att.net