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why still use C?

no this is no trollposting and please don't get it wrong but iam very
curious why people still use C instead of other languages especially C++.

i heard people say C++ is slower than C but i can't believe that. in pieces
of the application where speed really matters you can still use "normal"
functions or even static methods which is basically the same.

in C there arent the simplest things present like constants, each struct and
enum have to be prefixed with "struct" and "enum". iam sure there is much
more.

i don't get it why people program in C and faking OOP features(functi on
pointers in structs..) instead of using C++. are they simply masochists or
is there a logical reason?

i feel C has to benefit against C++.

--
cody

[Freeware, Games and Humor]
www.deutronium.de.vu || www.deutronium.tk
--
comp.lang.c.mod erated - moderation address: cl**@plethora.n et
Nov 13 '05
687 23872
Eric Backus wrote:
"P.J. Plauger" <pj*@dinkumware .com> wrote in message
..... snip ...
I can tell you that both the C and C++ committees were skeptical
at the outset and pretty thoroughly convinced in the end. They've
even agreed to *cooperate* [sic] to ensure that C and C++ remain
compatible in this area.


Is IBM really suggesting that new financial programs be written in
C? That doesn't sound like a very good idea. I can maybe see
putting support in hardware, if this really is a speed bottleneck
(which, frankly, I doubt) but why does a low-level language like C
need it? Surely a financial program would use C++ or something
higher level than that, and surely you would have some standard
class that deals with decimal arithmetic in a standard way. How
did they justify wanting to put it into C?


Many of us reactionary types do not consider C++ an improvement.
Especially when posting in c.l.c, c.l.c.m, c.s.c.

In point of fact even decimal FP will not avoid some of the
problems. Quite some time ago I had a payroll program, written in
Cobol (using decimal arithmetic), which I corrected to do better
rounding (by incorporating guard digits). The results sometimes
disagreed with some employees own calculations, which they rounded
to the penny at each stage. The employees rightly mistrusted all
computer programs, programmers, etc. :-)

I had to remove the guards to quiet the rebellion. There is a
moral here somewhere.

--
Chuck F (cb********@yah oo.com) (cb********@wor ldnet.att.net)
Available for consulting/temporary embedded and systems.
<http://cbfalconer.home .att.net> USE worldnet address!
--
comp.lang.c.mod erated - moderation address: cl**@plethora.n et
Nov 13 '05 #531
Eric Backus wrote:
....
Is IBM really suggesting that new financial programs be written in C? That
doesn't sound like a very good idea. I can maybe see putting support in
hardware, if this really is a speed bottleneck (which, frankly, I doubt) but
why does a low-level language like C need it? Surely a financial program
would use C++ or something higher level than that, and surely you would have
some standard class that deals with decimal arithmetic in a standard way.
How did they justify wanting to put it into C?


Because not everyone believes that financial programs have to be
high-level.
--
comp.lang.c.mod erated - moderation address: cl**@plethora.n et
Nov 13 '05 #532
Morris Dovey <mr*****@iedu.c om> wrote:
James Kuyper wrote:
It's not "high degrees of precision" that are needed. It's a
fairly low degree of precision, but it needs to be provided
exactly, which makes is similar in some ways to requiring
infinite precision.


I'm going to have to think about this statement for a while. I'm
mulling over simple arithmatic operations like 1/3, 1/7, etc.;
and asking myself: "What's improved by performing this operation
in FP-10?" Am I grossly missing the point?


People enter numbers - especially amounts of money - as decimal, usually
fixed-point numbers, and they expect an exact decimal result.
Mathematically, decimal FP is not really better than binary FP, but
psychologically there's a great deal of difference, since we humans
insist on doing things in powers of ten ourselves and expect the same
from computers.

Richard
--
comp.lang.c.mod erated - moderation address: cl**@plethora.n et
Nov 13 '05 #533
Mike Cowlishaw wrote:

Eric Backus wrote:

....
but why does a low-level language like C need it?
Surely a financial program would use C++ or something higher level
than that, and surely you would have some standard class that deals
with decimal arithmetic in a standard way. How did they justify
wanting to put it into C?


Again: how would one write that class without the primitive
types in the language?


You could do it rather inefficiently, as a wrapper for a scaled integer;
but then, that's precisely the point: it would be very inefficient.
--
comp.lang.c.mod erated - moderation address: cl**@plethora.n et
Nov 13 '05 #534
"CBFalconer " <cb********@yah oo.com> wrote in message
news:cl******** ********@pletho ra.net...
Eric Backus wrote:
Is IBM really suggesting that new financial programs be written in
C? That doesn't sound like a very good idea. I can maybe see
putting support in hardware, if this really is a speed bottleneck
(which, frankly, I doubt) but why does a low-level language like C
need it? Surely a financial program would use C++ or something
higher level than that, and surely you would have some standard
class that deals with decimal arithmetic in a standard way. How
did they justify wanting to put it into C?
Many of us reactionary types do not consider C++ an improvement.
Especially when posting in c.l.c, c.l.c.m, c.s.c.


And I might agree with those reactionary types--note that I didn't claim C++
was an improvement, just that C would probably not be used for a financial
program.
In point of fact even decimal FP will not avoid some of the
problems.


I'm sure that's true.

--
Eric Backus
R&D Design Engineer
Agilent Technologies, Inc.
425-356-6010 Tel
--
comp.lang.c.mod erated - moderation address: cl**@plethora.n et
Nov 13 '05 #535
"Mike Cowlishaw" <mf*****@attglo bal.net> wrote in message
news:cl******** ********@pletho ra.net...
Eric Backus wrote:
Is IBM really suggesting that new financial programs be written in C?


Not necessarily -- but remember that the interpreters and compilers
for just about every other language are written in C. Without the
decimal support in C, all these languages would have to switch to
assembler code to access the decimal instructions.
That doesn't sound like a very good idea. I can maybe see putting
support in hardware, if this really is a speed bottleneck (which,
frankly, I doubt)


See, for example, the 'telco' benchmark at:
http://www2.hursley.ibm.com/decimal/telco.html


First, thanks for posting some real arguments for decimal floating-point, I
hadn't actually seen any posted here yet.

However, as to your telco benchmark:

A. I expect that a real financial application would have to use database
accesses and when reading and writing its data, and would have to deal with
locking the database around critical changes and all that kind of stuff.
Which, I believe, would slow down I/O by at least an order of magnitude, so
I don't expect the decimal math to be the bottleneck in that case.

B. Don't forget Moore's law. It'll be at least, say, 5 years before you
could expect to have decimal floating-point in the C standard. By then,
computer hardware will be an order of magnitude faster, so even if decimal
math is the bottleneck in a real application today, it may not be by then.

If anything, don't the benchmark and the associated decimal floating-point
library you used prove that this *can* be solved without putting the
floating-point into hardware and into C?
but why does a low-level language like C need it?
Surely a financial program would use C++ or something higher level
than that, and surely you would have some standard class that deals
with decimal arithmetic in a standard way. How did they justify
wanting to put it into C?


Again: how would one write that class without the primitive
types in the language?


If I'm correct that you don't need hardware acceleration for this, you write
it using the existing primitive types, like you already have done. If I'm
wrong, I guess you resort to assembly.

Part of my objection to this is because it seems like a need only for one
specific application (very large financial programs). By that same
reasoning, should we build primitives into C for handling digital
signatures, because digital signatures are slow and hardware could be used
to speed them up? Should we add primitives to provide fast access to
high-quality random numbers, because getting good random numbers is a
problem in some kinds of Monte-Carlo simulations? Should we add primitives
for image manipulation, so that you can use C to do high-speed graphics on
today's graphics cards? I'm sure people could make a case for any of those,
but we need to have a really high bar before doing that kind of thing.

--
Eric Backus
R&D Design Engineer
Agilent Technologies, Inc.
425-356-6010 Tel
--
comp.lang.c.mod erated - moderation address: cl**@plethora.n et
Nov 13 '05 #536
Francis Glassborow wrote:
WG14 will take time to consider all the options but the
proposal from IBM is for something that is considerably more
than just a change of radix.
Understood. My interest is in ensuring that C doesn't become a
disjoint collection of 'bumps', both syntactically and functionally.
The second issue is that tuning math libraries to work
effectively requires a great deal of skill and time. You
cannot simply change the radix and expect everything else to
work.
I've written software floating-point libraries and am aware of
this. I do expect that the additional "features" will be
completely consistant with the existing syntax and function.
I think that the fact that a total of nearly 100 largely
sceptical 'experts' (some C some C++) have decided that they
should take (a lot more) time considering the issues might
suggest that there was more to do than to just flick a switch
for a different radix.
Of course it does. I'm acutely aware that while I'm only an
'ordinary user' and not an 'expert', it's at least partly my
responsibility to voice my concerns and ask the questions that
help me be an /informed/ ordinary user.

Dan Pop wrote:
If, however, the IBM proposal doesn't fit the C floating point
model, it would be sheer insanity to change the latter in
order to accomodate the IBM proposal.
Well said, Dan. I heartily agree.

Douglas A. Gwyn wrote:
Naturally it depends on details, but generally speaking it's a
relatively small burden compared to some other areas in which
C99 extended the language. Also, just because a system is
small doesn't mean that decimal floating point isn't important
to it. Some embedded systems would benefit greatly from better
support for this.
I'll take your word on the relative burden sizes; ditto for the
comments regarding /some/ small and embedded systems.

Mike Cowlishaw wrote:
It is indeed possible, with great care and skilled error
analysis, to use binary floating point for some financial
applications (especially those where no calculation takes
place .. numbers are just moved around). But it is hard and
unnecessarily complicated -- and as soon as the application is
modified or maintained, 'accidents' are just waiting to
happen. It's faster (given the hardware), simpler, and easier
to use base-10 arithmetic.
It's even possible to use FP-2 for financial applications where
calculations /do/ take place. Moreover, the need for great care
and skilled error analysis (I think) doesn't go away just because
the calculations are done in FP-10.

"Hard" and "complicate d" are relative and subjective and would
seem to have an inverse relationship with "understood ". If an
application using FP-10 is not understood by the modifier or
maintainer, then it, too, is an accident about to happen.

I've never had FP-10 hardware so I'll take you at your word
concerning "faster", "simpler", and "easier".
This would mean that one could never have both binary and
decimal FP data in the same program/structure.
True. Would that necessarily be a problem? The only occasions I
can imagine would be (one time) database conversions.

Richard Bos wrote:
People enter numbers - especially amounts of money - as
decimal, usually fixed-point numbers, and they expect an exact
decimal result. Mathematically, decimal FP is not really
better than binary FP, but psychologically there's a great
deal of difference, since we humans insist on doing things in
powers of ten ourselves and expect the same from computers.


I may be just an ordinary programmer; but even so I don't write
user interfaces to input or output monetary amounts in binary,
octal, or hex! The need to do conversions to/from digit
characters remains regardless of the FP radix. I'm not sure I buy
the psychology argument either - do you suppose any normal person
ever wonders about the representation of values inside their
calculator? How about their digital watch or microwave oven?

Questions:

[1] Assuming the standard were changed to include FP-10, will the
compiler producers consider the new standard non-relevant, given
that it covers hardware not now available anywhere in the world?

[2] Assuming availability of conforming compilers, what is the
wisdom of incorporating changes that cannot be used in any
production CPU/FPU on the planet? Are we ready to declare all
current production CPUs obsolete?

[3] What will be the cost of adding a second (if FP-10 doesn't
simply replace FP-2) floating-point processor to all CPUs? I
strongly suspect that most CPUs don't have that much "spare" real
estate; so this will almost certainly mean substantial redesign
of all current CPUs (incorporate additional addressing, bussing,
interrupts, clocking,..,lay out,power consumption [my head hurts])

[4] Would the application needs be met by a simpler, more direct
approach? If rounding is a problem, for example, could not logic
be added to current (FP-2,FP-16) FPUs to produce the desired
behaviors?
--
Morris Dovey
West Des Moines, Iowa USA
C links at http://www.iedu.com/c
Read my lips: The apple doesn't fall far from the tree.
--
comp.lang.c.mod erated - moderation address: cl**@plethora.n et
Nov 13 '05 #537
On Sat, 22 Nov 2003 03:04:04 +0000, Eric Backus wrote:
Part of my objection to this is because it seems like a need only for one
specific application (very large financial programs).


You are restricting financial applications to just the financial applications
that you know.
But think for instance about vending machines:
- small footprint, embedded applications
- C often used
- need financial calcalutions for transactions

In the past I have written code for various instantations of this stuff, in C.
I know many others (still) do so.

Rob Windgassen
--
comp.lang.c.mod erated - moderation address: cl**@plethora.n et
Nov 13 '05 #538
On Sat, 22 Nov 2003 03:04:04 +0000, Eric Backus wrote:
Part of my objection to this is because it seems like a need only for one
specific application (very large financial programs).


You are restricting financial applications to just the financial applications
that you know.
But think for instance about vending machines:
- small footprint, embedded applications
- C often used
- need financial calcalutions for transactions

In the past I have written code for various instantations of this stuff, in C.
I know many others (still) do so.

Rob Windgassen
--
comp.lang.c.mod erated - moderation address: cl**@plethora.n et
Nov 13 '05 #539
"Eric Backus" <er*********@al um.mit.edu> writes:
[...]
If anything, don't the benchmark and the associated decimal floating-point
library you used prove that this *can* be solved without putting the
floating-point into hardware and into C?


I think the relevant question is, will decimal floating-point be
implemented in hardware? If so, and if IBM isn't the only hardware
manufacturer to do it, then C should accomodate it.

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://www.sdsc.edu/~kst>
Schroedinger does Shakespeare: "To be *and* not to be"
(Note new e-mail address)
--
comp.lang.c.mod erated - moderation address: cl**@plethora.n et
Nov 13 '05 #540

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