Re: Any research putting c above ada?

[Steve Jones - JON <jon@hpodid2.eurocontrol.fr>]

haggedk1@ulysses.jhuapl.edu (CubanPete) writes:

[snip]
> Come on now Phil.  There is no language that produces software that
> works "more right" than another.  Software is either right or it is
> not.   Ada may have a great debugger but VMS types will argue all day
> about how much better the debuger is on the VAX but I dont see tons of
> UNIX folks in VMS classes.
On my last project we use C and Ada, the bug count in the Ada code was
over 1/3 that of the C code. And tracking down bugs in Ada is much easier,
the code falls over it tells you the brief reason (eg constraint error) and
the line at which the error was raised and the stack trace.  You can then add
exception handlers et al to secure the system. It provides in built range
checking and strong typing.

In C assigning to an unitialised pointer will cause either a crash or
wild behaviour and never tell you, in Ada it will crash and tell you why.
In Ada you can restrict the user from assigning between incompatible types,
you can data hide etc etc.

The bug count and cost of Ada is much less than that of C, just because some
of the bugs that occur regularly in C (int a[10]; a[10] = 4; anyone ?) cannot
be done in Ada.  Both Ada and C can produce correct programs but IME it is
easier to do in Ada, the same would go for Eiffel v C++, a HLL v a MLL presents
similar advantages to a MLL over a LLL.

I know C, I know Ada and various languages besides, if I was writting a quick
check or hack I'd use C, if writting a large system I'd use Ada.  The advantage
of Ada isn't in the debugger but in the compiler, eg

C:
typedef int cleared_flight_level;
typedef int airspeed;

airspeed a = 4;
cleared_flight_level cfl = 5;

...

cfl = a;

...

This is a silly example as why would anyone _want_ to do it.  But Ada would
prevent you ever doing it.  It is here that the power comes in, with tools
like generics and a proper tasking model, decent hardware access is included
and data protection, all of these things make it harder to mess up, and easier
to check, if the range of an enumeration in C is changed a switch statement
will not care if the new value is not included, in Ada the compiler will fail
the code.

C is popular, it is quick and dirty, but I wouldn't like to trust my life to
it.

[snip]
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