Dear all,
I had this following doubt,while java is able to carryon with out
pointers why C language cant be modified to remove pointer?Hows java
able to do this with out pointers?
I jus plead sorry to those who advice me to post it to java people
because I have already done it.
Jus want to know alternatives to pointers which can be used with
C.While pointers provide flexibility most bugs are with respect to
pointers.So will it not be good if we are able to either forgo the
pointers or do some sort of modification(I am not aware how,but it can
be considered for research) so that our s/w s are more pure with out
bugs?
I am sorry for my amature query,but it will be helpful and I will be
thankful to all who makes me understand this.
Regards,
s.subbarayan
Nov 14 '05
19  1632 
In <pa************ *************** *@sig.now> August Derleth <se*@sig.now> writes: On Fri, 21 May 2004 18:51:57 +0100, Malcolm wrote:
You could try writing a "C--" (without pointers).
The name 'C--' is already in use: It's a language even lower-level than C
that is being touted as a compiler backend language.
http://www.cse.ogi.edu/PacSoft/projects/C--/
It's already in use by how many people?
Dan
--
Dan Pop
DESY Zeuthen, RZ group
Email: Da*****@ifh.de
In <c3************ **************@ posting.google. com> s_**********@re diffmail.com (s.subbarayan) writes: I had this following doubt,while java is able to carryon with out
pointers
Not true. It just doesn't call them pointers and doesn't make as flexible
as the C pointers.
why C language cant be modified to remove pointer?
Try to engage your brain and explain the advantages of a C without
pointers. What class(es) of applications would be better addressed by
such a language?
Removing pointers from C simply because newbies have a hard time getting
them right is NOT going to happen: one is supposed to be a C newbie for
a few months and something better than that for the rest of his life as a
C programmer...
Dan
--
Dan Pop
DESY Zeuthen, RZ group
Email: Da*****@ifh.de
"s.subbaray an" <s_**********@r ediffmail.com> wrote in message
news:c3******** *************** ***@posting.goo gle.com... I had this following doubt,while java is able to carryon with out
pointers why C language cant be modified to remove pointer?Hows java
able to do this with out pointers?
Removing pointers from C is like removing the gas pedal from a car. It'd be
a lot easier to learn, but you wouldn't get anywhere.
References in Java, Perl, etc. are just pointers with garbage collection and
other abstractions to make them "safe". This conflicts with the primary
goal of C, which is to be as close to assembly as possible while remaining
(mostly) portable. Since the machine deals in pointers, any abstraction
above that necessarily means a loss in run-time efficiency.
Jus want to know alternatives to pointers which can be used with
C.
There is no alternative to pointers in a non-trivial C program because
they're a fundamental part of the language. If you want a language that
hides pointers from you, go learn Java or Perl.
While pointers provide flexibility most bugs are with respect to
pointers.
Perhaps among novices, but not among experienced programmers. Being able to
use pointers correctly is a key attribute of someone who really understands
C.
S
--
Stephen Sprunk "Stupid people surround themselves with smart
CCIE #3723 people. Smart people surround themselves with
K5SSS smart people who disagree with them." --Aaron Sorkin
s.subbarayan <s_**********@r ediffmail.com> wrote: Dear all,
I had this following doubt,while java is able to carryon with out
pointers why C language cant be modified to remove pointer?Hows java
able to do this with out pointers?
I jus plead sorry to those who advice me to post it to java people
because I have already done it.
Jus want to know alternatives to pointers which can be used with
C.While pointers provide flexibility most bugs are with respect to
pointers.So will it not be good if we are able to either forgo the
pointers or do some sort of modification(I am not aware how,but it can
be considered for research) so that our s/w s are more pure with out
bugs?
I am sorry for my amature query,but it will be helpful and I will be
thankful to all who makes me understand this.
Regards,
s.subbarayan
You got things wrong: Every object is a pointer in Java. You just don't see
it. Basic types such as int and short are not pointers. But everything else is.
--
Viktor Lofgren, Umea, Sweden
Mainly self-eductated UNIX programmer, running Slackware-current. mw*****@newsguy .com (Michael Wojcik) writes: In article <cu************ *@zero-based.org>, Martin Dickopp <ex************ ****@zero-based.org> writes: Eric Sosman <Er*********@su n.com> writes:
> Malcolm wrote:
>> All computer programs need to address memory (ie use pointers)
>> internally.
>
> Off-topic nit: Alan Turing demonstrated that this is false.
Even a Turing machine has a "pointer" as a part of its state: the
current tape position.
An n-PDA (n > 1) is equivalent to a TM. I don't see any pointer-
equivalent in an n-PDA.
I would consider a top-of-stack position a pointer.
Martin
--
,--. Martin Dickopp, Dresden, Germany ,= ,-_-. =.
/ ,- ) http://www.zero-based.org/ ((_/)o o(\_))
\ `-' `-'(. .)`-'
`-. Debian, a variant of the GNU operating system. \_/
"Dan Pop" <Da*****@cern.c h> wrote in message
Try to engage your brain and explain the advantages of a C without >
pointers. What class(es) of applications would be better addressed > by
such a language?
My MiniBasic doesn't use pointers. There is no PEEK or POKE. However it does
have a DIM statement and it is possible to redimension arrays, which of
course calls malloc() internally. Trying an out-of-bounds access will cause
an error.
The advantage of MiniBasic is that it is impossible, barring bugs on my
part, to cause undefined behaviour. The idea is to allow programs to be
extended by anyone who learnt a bit of BASIC from having a microcomputer
back in the olden days.
On Mon, 24 May 2004 14:24:55 +0000, Dan Pop wrote: In <pa************ *************** *@sig.now> August Derleth <se*@sig.now>
writes:
On Fri, 21 May 2004 18:51:57 +0100, Malcolm wrote:
You could try writing a "C--" (without pointers).
The name 'C--' is already in use: It's a language even lower-level than
C that is being touted as a compiler backend language.
http://www.cse.ogi.edu/PacSoft/projects/C--/
It's already in use by how many people?
Well, the implementors, for a few.
Good point, I suppose: C-- is probably a solution looking for a problem,
at least at this stage. Maybe when seriously complex hardware
architectures filter down to the mass-market PCs (for example, RISC-like
out-of-order execution and VLIW slot-filling), compiler designers will
want to palm off as much of the /real/ hard work to the backend folks,
making intermediate languages more interesting.
August "EPIC challenges to compiler design..." Derleth
--
yvoregnevna gjragl-guerr gjb-gubhfnaq guerr ng lnubb qbg pbz
To email me, rot13 and convert spelled-out numbers to numeric form.
"Makes hackers smile" makes hackers smile.
In article <cu************ *@zero-based.org>, Martin Dickopp <ex************ ****@zero-based.org> writes: mw*****@newsguy .com (Michael Wojcik) writes:
In article <cu************ *@zero-based.org>, Martin Dickopp <ex************ ****@zero-based.org> writes: Eric Sosman <Er*********@su n.com> writes:
> Malcolm wrote:
>> All computer programs need to address memory (ie use pointers)
>> internally.
>
> Off-topic nit: Alan Turing demonstrated that this is false.
Even a Turing machine has a "pointer" as a part of its state: the
current tape position.
An n-PDA (n > 1) is equivalent to a TM. I don't see any pointer-
equivalent in an n-PDA.
I would consider a top-of-stack position a pointer.
Sigh. I was going to address this proleptically, then didn't out
of laziness.
I can see the argument for calling the current tape position in a
TM a "pointer". It marks one of the positions on the tape as
current. Machine operations can change it.
The top of the stack in a PDA is not a pointer in any useful sense.
What makes a pointer a pointer per se is that it can be changed to
point to a different object. The top of the stack "points" to only
one thing: whatever is currently on top of the stack. "Changing"
this "pointer" has side effects: it's either a pop, which is a
destructive operation, or a push, which has much more limited
semantics than a "move tape" (or equivalently "move tape pointer")
operation.
Calling the top of the stack a pointer in this sense is uninteresting.
It's equivalent to calling any variable a "pointer". (That a stack
can be implemented with a moving pointer is utterly beside the point.)
--
Michael Wojcik mi************@ microfocus.com
Every allegiance to some community eventually involves such a fetish,
which functions as the disavowal of its founding crime: is not 'America'
the fetish of an infinitely open space enabling every individual to
pursue happiness in his or her own way? -- Slavoj Zizek
Viktor Lofgren <zw*@eudial.n os--pam.mine.nu> scribbled the following: s.subbarayan <s_**********@r ediffmail.com> wrote: Dear all,
I had this following doubt,while java is able to carryon with out
pointers why C language cant be modified to remove pointer?Hows java
able to do this with out pointers?
I jus plead sorry to those who advice me to post it to java people
because I have already done it.
Jus want to know alternatives to pointers which can be used with
C.While pointers provide flexibility most bugs are with respect to
pointers.So will it not be good if we are able to either forgo the
pointers or do some sort of modification(I am not aware how,but it can
be considered for research) so that our s/w s are more pure with out
bugs?
I am sorry for my amature query,but it will be helpful and I will be
thankful to all who makes me understand this.
You got things wrong: Every object is a pointer in Java. You just don't see
it. Basic types such as int and short are not pointers. But everything else is.
Your terminology is lax. Objects are not pointers or vice versa. Every
object *variable* is really an object *pointer* variable in Java, but
the things those variables' values point at are real, honest-to-gosh,
all-signing, all-dancing objects. How do you suppose pointers with
nothing to point at could ever be of any use?
--
/-- Joona Palaste (pa*****@cc.hel sinki.fi) ------------- Finland --------\
\-- http://www.helsinki.fi/~palaste --------------------- rules! --------/
"Remember: There are only three kinds of people - those who can count and those
who can't."
- Vampyra
Michael Wojcik wrote: In article <cu************ *@zero-based.org>, Martin Dickopp <ex************ ****@zero-based.org> writes:
mw*****@newsg uy.com (Michael Wojcik) writes:
In article <cu************ *@zero-based.org>, Martin Dickopp <ex************ ****@zero-based.org> writes:
Eric Sosman <Er*********@su n.com> writes:
>Malcolm wrote:
>
>>All computer programs need to address memory (ie use pointers)
>>internall y.
>
> Off-topic nit: Alan Turing demonstrated that this is false.
Even a Turing machine has a "pointer" as a part of its state: the
current tape position.
An n-PDA (n > 1) is equivalent to a TM. I don't see any pointer-
equivalent in an n-PDA.
I would consider a top-of-stack position a pointer.
Sigh. I was going to address this proleptically, then didn't out
of laziness.
I can see the argument for calling the current tape position in a
TM a "pointer". It marks one of the positions on the tape as
current. Machine operations can change it.
Rhetorical question: If you were building a Turing machine,
how many bits would you use to hold the value of this "pointer?"
(Hint: The tape has a countably infinite number of cells.)
Rhetorical question: Since Turing himself allocated zero bits
of his conceptual machine to designate the position of "HERE,"
how many different values can his "pointer" take on? (Hint:
What is the Shannon entropy of a constant signal?)
Calling the top of the stack a pointer in this sense is uninteresting.
It's equivalent to calling any variable a "pointer". (That a stack
can be implemented with a moving pointer is utterly beside the point.)
Exactly -- just as in the case of "HERE" in a Turing machine.
-- Er*********@sun .com This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics | |
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