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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
On 10 Dec 2003 09:18:09 GMT in comp.lang.c.mod erated, Da*****@cern.ch
(Dan Pop) wrote:
In <cl************ ****@plethora.n et> glen herrmannsfeldt <ga*@ugcs.calte ch.edu> writes:
It gets conformance with the results people get on pocket calculators,
or when they do long division by hand on paper.


Why is such conformance (up to the last digit) important?


Transactional systems have to get the numbers exact: for example, when
companies or banks are settling accounts between themselves, and a
single cheque is written (or EFT generated) to settle each day's or
month's accounts, that cheque must be for exactly the same number as
if each transaction was settled by a separate cheque (or EFT).

Adding machines / calculators are still used to spot check / audit
results from systems and the results are expected to be exactly the
same. The bean counters get very upset if a result from a new system
run on old data is not exactly the the same as the result they got
from the old system.

I've been on projects where we worked for a month on a penny
discrepancy -- the final result on the new system was out by a penny
from the old system -- but every intermediate value we checked was
identical, and the final total was being calculated correctly without
any loss of precision (in binary FP) -- the systems project lead gave
the business project lead a penny, and he signed off on the system at
last.
--
Thanks. Take care, Brian Inglis Calgary, Alberta, Canada

Br**********@CS i.com (Brian dot Inglis at SystematicSw dot ab dot ca)
fake address use address above to reply
--
comp.lang.c.mod erated - moderation address: cl**@plethora.n et
Nov 14 '05 #631
Douglas A. Gwyn wrote:
Dan Pop wrote:
If PL/I had any compelling merits, I'm sure it would have caught on,
sooner or later. It was certainly not lack of availability of
implementations that caused its failure.
PL/I was moderately successful; for example MULTICS was
implemented in PL/I, and a lot of IBM systems programming
was done in PL/I.


PL/I failed to do what IBM wanted, which was to replace Fortran
and COBOL. I believe that there was once a plan not to write
Fortran or COBOL compilers for S/360.

Though around that time it was not obvious that S/360 would be
the success it turned out to be.

I am pretty sure that no-one at the time expected S/360 software
to still run on computers build 40 years later. I have recently
seen reports of testing the S/360 PL/I and Fortran compilers on
OS/390 and z/OS on current machines. They do still run!

PL/I was over ambitious for the machines that existed at the time.

-- glen
--
comp.lang.c.mod erated - moderation address: cl**@plethora.n et
Nov 14 '05 #632
CBFalconer wrote:
glen herrmannsfeldt wrote: (snip)
As I
understand the proposals, they store numbers in memory with each
three digits stored into 10 bits, though in registers they are
BCD. The memory format is only slightly less efficient than
binary, partly made up since fewer exponent bits are required for
the desired exponent range.

Think about how you would normalize such a value. That would not
be a decimal format, that would be a base 1000 format. The count
of significant digits would jitter over a range of 3!


The normalization is done in uncompressed (BCD) form, and then
they are converted to the base 1000 form for storage.

So 50 bits would store 15 decimal digits, so 54 would store 16.
With sign, that would leave nine for an exponent, which would allow
an exponent between -128 and +127. (Some exponent values may be
reserved, though.) 16 decimal digits hold between 49.8 and 53.1 bits
A decimal 9 bit exponent representing 10**-256 though 10**255 is
equivalent to 10.7 bits of binary exponent.

So, sign+exponent+m antissa it is equivalent to 1+49.8+10.7=61. 5 bits,
or 61.5/64.0=96% efficient in the worst case, and 64.8/64.0=100.1% in
the best case. About 98% on average.

-- glen
--
comp.lang.c.mod erated - moderation address: cl**@plethora.n et
Nov 14 '05 #633
In article <cl************ ****@plethora.n et>,
glen herrmannsfeldt <ga*@ugcs.calte ch.edu> wrote:
The normalization is done in uncompressed (BCD) form, and then
they are converted to the base 1000 form for storage.

So 50 bits would store 15 decimal digits, so 54 would store 16.
With sign, that would leave nine for an exponent, which would allow
an exponent between -128 and +127. (Some exponent values may be
reserved, though.) 16 decimal digits hold between 49.8 and 53.1 bits
A decimal 9 bit exponent representing 10**-256 though 10**255 is
equivalent to 10.7 bits of binary exponent.

So, sign+exponent+m antissa it is equivalent to 1+49.8+10.7=61. 5 bits,
or 61.5/64.0=96% efficient in the worst case, and 64.8/64.0=100.1% in
the best case. About 98% on average.


The proposed format for decimal numbers is just very slightly more
efficient: The 64 bit format uses indeed 50 bits for 15 decimal digits.
Then it uses 5 bits which can hold 32 values to encode one decimal
digits, three values (-1, 0, 1) that will become part of the exponent,
and two values encode infinity and NaN.

One bit is used for the sign, 8 more bits for the decimal exponent, so
you have 768 values for the exponent from -384 to +383.
--
comp.lang.c.mod erated - moderation address: cl**@plethora.n et
Nov 14 '05 #634
>> With SMT, processors are going the other way. One floating point
unit used by two processors. The additional logic to generate a
decimal ALU relative to a binary ALU is pretty small. As I
understand the proposals, they store numbers in memory with each
three digits stored into 10 bits, though in registers they are
BCD. The memory format is only slightly less efficient than
binary, partly made up since fewer exponent bits are required for
the desired exponent range.


Think about how you would normalize such a value. That would not
be a decimal format, that would be a base 1000 format. The count
of significant digits would jitter over a range of 3!


Well first of all, why would one normalize? [See the FAQ at
http://www2.hursley.ibm.com/decimal/decifaq.html part 4,
for a discussion.]

Also, the base 1000 is used only for storage; all computations,
rounding, etc., are carried out in base 10.

Mike Cowlishaw
--
comp.lang.c.mod erated - moderation address: cl**@plethora.n et
Nov 14 '05 #635
glen herrmannsfeldt wrote:
CBFalconer wrote:
glen herrmannsfeldt wrote:


(snip)
As I understand the proposals, they store numbers in memory
with each three digits stored into 10 bits, though in
registers they are BCD. The memory format is only slightly
less efficient than binary, partly made up since fewer
exponent bits are required for the desired exponent range.

Think about how you would normalize such a value. That would
not be a decimal format, that would be a base 1000 format. The
count of significant digits would jitter over a range of 3!


The normalization is done in uncompressed (BCD) form, and then
they are converted to the base 1000 form for storage.


If you have ever designed a floating point package you will
realize that normalization takes up the majority of the time. It
needs to be simple, not a major base conversion.

Any reasonable form of decimal FP will be based on some flavor of
bcd, possibly 8421, or excess 3, or 2*421, or even bi-quinary.

--
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 14 '05 #636
ge***@mail.ocis .net (Gene Wirchenko) writes:
glen herrmannsfeldt <ga*@ugcs.calte ch.edu> wrote:
I believe that processors should now have float decimal, though I don't
know that I would ever use it. It would almost be worthwhile not to
have to read newsgroup posts from people who don't understand binary
floating point.


While we are at it, let us do the same for integer arithmetic.
That way, we need never again see "I think my compiler has a bug. My
program keeps giving wrong answers. It says that 5/3 equals 1."


Good idea. Many programming languages have adopted this idea,
using a different operator than "/" for truncating integer division.

--
Fergus Henderson <fj*@cs.mu.oz.a u> | "I have always known that the pursuit
The University of Melbourne | of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh> | -- the last words of T. S. Garp.
--
comp.lang.c.mod erated - moderation address: cl**@plethora.n et
Nov 14 '05 #637
Fergus Henderson <fj*@cs.mu.oz.a u> wrote:
ge***@mail.oci s.net (Gene Wirchenko) writes:
glen herrmannsfeldt <ga*@ugcs.calte ch.edu> wrote:
I believe that processors should now have float decimal, though I don't
know that I would ever use it. It would almost be worthwhile not to
have to read newsgroup posts from people who don't understand binary
floating point.
While we are at it, let us do the same for integer arithmetic.
That way, we need never again see "I think my compiler has a bug. My
program keeps giving wrong answers. It says that 5/3 equals 1."


Good idea. Many programming languages have adopted this idea,
using a different operator than "/" for truncating integer division.


And here I thought that "/" was the different operator, used
instead of

*

*****

*

Sincerely,

Gene Wirchenko



--
Fergus Henderson <fj*@cs.mu.oz.a u> | "I have always known that the pursuit
The University of Melbourne | of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh> | -- the last words of T. S. Garp.
--
comp.lang.c.mo derated - moderation address: cl**@plethora.n et


Computerese Irregular Verb Conjugation:
I have preferences.
You have biases.
He/She has prejudices.
--
comp.lang.c.mod erated - moderation address: cl**@plethora.n et
Nov 14 '05 #638
Christian Bau wrote:
In article <cl************ ****@plethora.n et>,
glen herrmannsfeldt <ga*@ugcs.calte ch.edu> wrote:
The normalization is done in uncompressed (BCD) form, and then
they are converted to the base 1000 form for storage. So 50 bits would store 15 decimal digits, so 54 would store 16.
With sign, that would leave nine for an exponent, which would allow
an exponent between -128 and +127. (Some exponent values may be
reserved, though.) 16 decimal digits hold between 49.8 and 53.1 bits
A decimal 9 bit exponent representing 10**-256 though 10**255 is
equivalent to 10.7 bits of binary exponent. So, sign+exponent+m antissa it is equivalent to 1+49.8+10.7=61. 5 bits,
or 61.5/64.0=96% efficient in the worst case, and 64.8/64.0=100.1% in
the best case. About 98% on average.

The proposed format for decimal numbers is just very slightly more
efficient: The 64 bit format uses indeed 50 bits for 15 decimal digits.
Then it uses 5 bits which can hold 32 values to encode one decimal
digits, three values (-1, 0, 1) that will become part of the exponent,
and two values encode infinity and NaN.

One bit is used for the sign, 8 more bits for the decimal exponent, so
you have 768 values for the exponent from -384 to +383.


I had remembered the three digits in 10 bits form. The rest was just
a guess as to how it possibly could be done.

OK, so still between 49.8 and 53.1 equivalent bits for the mantissa,
11.3 bits for the exponent, and 1 for the sign, so 62.1 worst case
and 65.4 best case, for 63.75 average case, or 99.6% efficient.

This reminds me of all the work the authors of the original Fortran
compiler did to generate as efficient object code as possible.
They needed to convince people that Fortran could be used in place
of assembly code, without a significant loss of efficiency.

Personally, I would have been happy with ordinary BCD arithmetic,
in floating point form. It seems to have worked well for calculator
users for many years now.

-- glen
--
comp.lang.c.mod erated - moderation address: cl**@plethora.n et
Nov 14 '05 #639
Gene Wirchenko wrote:
Fergus Henderson <fj*@cs.mu.oz.a u> wrote:
ge***@mail.oc is.net (Gene Wirchenko) writes: (snip)
While we are at it, let us do the same for integer arithmetic.
That way, we need never again see "I think my compiler has a bug. My
program keeps giving wrong answers. It says that 5/3 equals 1."
Good idea. Many programming languages have adopted this idea,
using a different operator than "/" for truncating integer division.

And here I thought that "/" was the different operator, used
instead of

*

*****

*

The calculator in Microsoft windows has a / on the divide key.

Some time ago, my son was asking how to input fractions into
the calculator, and I showed him the key used to do it.

1 / 3 = and you get one third.

(He already knew that it was the divide key.)

-- glen
--
comp.lang.c.mod erated - moderation address: cl**@plethora.n et
Nov 14 '05 #640

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