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Agree, the later makes no sense.
I'm not sure how many cookies it makes to be happy, but so far it's not 27.
JaxCoder.com
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The latter may be the better notation since I can declare;
int *pa, a;
where pa is a pointer to an int and a is an int. If I declare
int* pa, a;
this is also legal, where pa is still a point to an int and a is an int.
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I was just to reply with the same.
I always put the * modifier RIGHT in front of the variable. And it makes sense since, "char *" is not really the type. A lot of beginners are confused when something like the following:
char* psz, pszHi, pszBye;
and they discover pszHi / pszBye are just character variables.
Code like the following helps those initiates:
char *psz, *pszHi, *pszBye, chA, chB, *pszString3;
Just my $0.02.
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They are literally half backward. In order to understand a C type definition, you ping-pong between the part before the name and the part after, until all tokens have been processed.
If there is one single thing for K&R ought to have been taken out and shot, this is it!
Freedom is the freedom to say that two plus two make four. If that is granted, all else follows.
-- 6079 Smith W.
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Let it Rust!
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The usage is odd as well:
char* p = ...
*p = 'x'; Vs
foo f;
foo *pf = &f;
f.x = '?';
pf->x = '!'; Why invent two access operators "." and "->", when you could just use "*pf.x" and be more consistent? Or use "->" to dereference all pointers?
I get the feeling bits of the C spec were thrown in just before the submission deadline ...
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
"Common sense is so rare these days, it should be classified as a super power" - Random T-shirt
AntiTwitter: @DalekDave is now a follower!
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Quote: Why do we do this? I'll tell you... I don't know. But because of this, every one of us knows what a pointer is, how to dereference it, and what K&R expect of him.
With apologies to Sholem Aleichem and to the producers of Fiddler on the Roof
Freedom is the freedom to say that two plus two make four. If that is granted, all else follows.
-- 6079 Smith W.
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Beautiful. I'm proud of you.
Ravings en masse^ |
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"The difference between genius and stupidity is that genius has its limits." - Albert Einstein | "If you are searching for perfection in others, then you seek disappointment. If you seek perfection in yourself, then you will find failure." - Balboos HaGadol Mar 2010 |
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If you read it in reverse it can make more sense:
char * sz;
char sz[1024];
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The floating asterisk looks lonely!
Real programmers use butterflies
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There's a stricter formal rule, called the Right-Left rule.
I wrote my only technical article on CP more than 15 years back on just this: How to interpret complex C/C++ declarations
Cheers,
विक्रम
"We have already been through this, I am not going to repeat myself." - fat_boy, in a global warming thread
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Yes, but I could not remember it. I know it's important when typedef 'ing function pointers.
I just reread your article - very interesting, and should be required reading for all the QA kiddies.
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char* means you should read the footnote.
* array declarations in C may or may not be consistent.
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Stop whining.
Declarations made easy.
Computer Language Magazine, May, 1991.
If you can keep your head while those about you are losing theirs, perhaps you don't understand the situation.
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Without wishing to start a major language debate, I think its important to understand that C was designed to be efficient at using the underlying hardware of the machine, and the way things are declared reflects this:
char *sz declares a single variable that points to a place in memory, supposedly holding a char value. This pointer (and here's where dragons lie!) can be made to point to anywhere and to anything regardless of its declaration, you are just telling the compiler that at the place where that pointer points, YOU consider there to be a char value (whether it is or not in reality).
char sz[1024] says that at the address represented by sz is a reserved block of memory that holds (in theory) 1024 char items.
In your code you can (with some severe caveats!) use both variables in the same way and it's up to you to remember and manage whatever you think you are looking at in that location - this is both the beauty and danger of a language like C - it allows you to manipulate things in much the same way as in assembler and with as few restrictions, but it provides no protection against you doing something stupid.
However, even the early compilers would detect if you attempted to treat these two variables as exactly equivalent, but would often only warn rather than prevent it, allowing you to create absolute havoc.
Much code rot is caused by the developer incorrectly assuming that, by default, either of these variables is initialised (which is why most compilers these days will attempt to put something sensible in newly declared variables to protect the innocent). Before initialisation char *sz may contain a random address and even attempting to look at it might cause a total system crash if it accidentally points into hardware protected memory. With char sz[1024] though you can be sure that doing char x = *sz is safe because sz already holds a valid address and points into memory allocated to your program, what you don't know is what value you will actually get back from that place before the array is initialised.
Why have I bored you all with this stuff? Because so many developers these days seem to know absolutely nothing at all about how the hardware they are driving works - that's fine if you are writing in a high-level domain specific language where everything like that is hidden - no help at all if you are writing a device driver for some complex piece of hardware that is integrated into an operating system of some sort.
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I think you may have misunderstood me
char[] sz = char[100];
would be more consistent even if it requires extra typing.
I'm not complaining about the way accessed either, just how it's declared. I don't mind that either way sz can be accessed via pointer or array index.
In this case you could dereference it with a * like you can otherwise. I'm not arguing you shouldn't be able to.
It's not a huge deal for me either. I've coded in the C and C++ for years so I'm used to it.
It's just a syntax wrinkle i don't like.
Real programmers use butterflies
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You, in your last paragraph, point out my pet peeve with C#;
Everything is separated by '.' - it makes things easier and detaches the developer from what the object really is. Value in enum? Member in a class? Namespace?
OK - they worked to make all of this (seem to) work together, smoothly, but it also, by shielding the users from reality, fosters and allows the maintenance of a degree of ignorance. Essentially, C# is a dumbed-down version of C++ . Hardly a surprise as the original stated intent of MicroSloth, when they created it, was to wean users away from vb.NET .
Probably this type of pseudo-rant "points" to my stogie attitude developed with age. Or that I learned assembler before C .
Quick Anecdote: when my brother got his first computer I worked on getting him to master DOS (a while ago!). At first he started but then he stopped: they installed Windows. I asked him how he'll fix anything if there's a problem, without understanding what Windows was running on. His answer? He'll ask me.
And so it goes with C# vs C/C++ background developers.
Ravings en masse^ |
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"The difference between genius and stupidity is that genius has its limits." - Albert Einstein | "If you are searching for perfection in others, then you seek disappointment. If you seek perfection in yourself, then you will find failure." - Balboos HaGadol Mar 2010 |
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Java's stupid (=political) C compatibility
C started as a simple language on top of assembly language. Lingual considerations of abstractional consistency had no priority. As error awareness. Everything is an int, boolean, pointer, array, functions.
In fact declarations have a weird kind of syntax requiring a large parsing. Or for a human a bit of back-and-forth reading.
As java was launched, it intended to improve some parts of C++/C. So in java the entire type info becomes separate from the variable.
char[] jarr;
But as novice java kept the C style for accustomed C/C++ programmmers:
char jarr[];
If one looks at java's:
char[] jarr = new char[1024];
one get's an idea why C chose:
char str[1024];
The 1024 is not part of the `char*` data structure as field, but some compile time allocation.
In general one should accept C as it is: a compiler strong, thin layered, fun language.
For language features it is pedagogical unsuited w.r.t. type systems, actual data, error prevention and so on. Taking any language, like a simple Pascal, might give less confusion with pointer versus array like in parameter passing. Then going back to C one sees that arrays are passed as pointers i.o. the pointed-to data as in Pascal.
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When I was learning C, it bothered and confused me. Now, I recognized it as the type and it doesn't bother me. Is that age, tolerance, or just exposure to too many languages???
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Yeah I've coded in C and C++ for a long time, to the point where it doesn't confuse me. I just don't like the inconsistency. I understand why it is from a syntax perspective.
In c#
int[] array = new int[10];
But in C it doesn't make sense to use new, and int[10] array; is ugly.
Still, it just bugs me, because they're both type modifiers.
Real programmers use butterflies
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You are thinking about it the wrong way, I believe.
There is an implicit Algebra: * = 1/&
so, char *p, LITERALLY says (*p) is a char.
therefore &(*p) => Address of that char!
but knowing the algebra & and * cancel each other out (as do & and [)
So, p is a pointer to a specific char. And the beauty of this, is that how you declare it usually implies how you are going to use it. A fixed array is declared as char a[10]; Which again, says (to me), I want an array of 10 characters, a POINTS to the first character, and a[1] == *(a+1).
I always found this part of C very expressive and self-explanatory.
Of course, I learned PDP/11 Macro-11 Assembly BEFORE I learned C. So most of this was mapping to register level access of R0 vs (R0) [Memory direct and indirect addressing].
Mov 65, R0 ; Stores the value in the register
Mov 65, (R0) ; Stores 65 at the memory location of R0
Mov 65, (R0++) ; Stores 65 at the memory location and increments the memory location AFTER to the next
; Note its been 35 years, the syntax is illustrative of the features.
If you know how the variable is declared, you should instantly understand the various ways you can dereference it.
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