strtoint

[Gordon Burditt]

Re: strtoint

>>trouble me. Why not make an array of the set of characters you want[color=blue][color=green]
>>to be in the random string and then randomly select from the set of[/color]
>
>Well they aren't so magic 65 is equal to A and 25 is the range
>of the Alphabet :-) so the generated string will be between
>(A-Z)[/color]

Yes, they *ARE* magic.

C does not guarantee ANY of:

'A' == 65
'A' + 25 == 'Z'
The character set is ASCII.
The alphabet contains 25 or 26 letters.
There are no unaccented letters in the character set.
Alphabetic characters form a contiguous block of consecutive codes.

Gordon L. Burditt

[Al Bowers]

Re: strtoint



Profetas wrote:
[color=blue][color=green]
>>Well that is not a bad approach. However the magic numbers 65 and 25
>>trouble me. Why not make an array of the set of characters you want
>>to be in the random string and then randomly select from the set of[/color]
>
>
> Well they aren't so magic 65 is equal to A and 25 is the range
> of the Alphabet :-) so the generated string will be between
> (A-Z)
>[/color]

You know, I have just searched the standard, and I find no mention
of the value of 'A' being 65. But I did find in this paragraph

5.2.1.1
"The values of the members of the execution character set
are implementation-defined."

So you may be using a implementation-defined solution.

This news group is dedicated to the language as defined by the
C Standard(ISO/IEC 9899:1999). Again, I point out that in this
newsgroup, with readers that use various implementations , that
your assertion that 'A' is value 65 is idiotic.


--
Al Bowers
Tampa, Fl USA
mailto: xabowers@myrapi dsys.com (remove the x to send email)

http://www.geocities.com/abowers822/

[Emmanuel Delahaye]

Re: strtoint

Peter Nilsson wrote on 26/07/04 :
[color=blue][color=green]
>> Bare in mind that in C, '=' is the affectation operator,[/color]
>
> I think 'affectation' must be a French/English faux ami.[/color]

Oops, I meant assignment, of course. Sorry for the Frenchism!

--
Emmanuel
The C-FAQ: http://www.eskimo.com/~scs/C-faq/faq.html

"C is a sharp tool"

[Chris Torek]

Re: strtoint

In article
<5d524b0f489587 974ff7e5f36c82d a65@localhost.t alkaboutprogram ming.com>
Profetas <xuxu_18@yahoo. com> writes:[color=blue]
>Well they aren't so magic 65 is equal to A and 25 is the range
>of the Alphabet :-) so the generated string will be between
>(A-Z)[/color]

Except that 'A' is 193 (0xC1), on that IBM mainframe using EBCDIC.
(And yes, it has a C compiler.) Not only that, while 'A'+1 is 'B',
and 'B'+1 is 'C', there is an odd gap so that 'I'+1 is not 'J' --
'J' is coded as 0xD1. There is another gap before the end of the
alphabet, and '0' is coded as 0xF0.
--
In-Real-Life: Chris Torek, Wind River Systems
Salt Lake City, UT, USA (40°39.22'N, 111°50.29'W) +1 801 277 2603
email: forget about it http://web.torek.net/torek/index.html
Reading email is like searching for food in the garbage, thanks to spammers.

[Old Wolf]

Re: strtoint

Emmanuel Delahaye <emdel@YOURBRAn oos.fr> wrote:[color=blue]
> Profetas wrote on 25/07/04 :[color=green]
> > does this function exist in c? on any equivalent? that convert string to
> > integer?
> >
> > how do I convert a array to a "string"
> > example
> > char arr['a','b','c'];[/color]
>
> This is not C.[/color]

Actually it is; if the system uses ASCII then it declares an
array of 99 chars.

[Peter Nilsson]

Re: strtoint

"Gordon Burditt" <gordonb.ibq1o@ burditt.org> wrote in message
news:ce1m6e$i76 @library2.airne ws.net...[color=blue][color=green][color=darkred]
> >>trouble me. Why not make an array of the set of characters you want
> >>to be in the random string and then randomly select from the set of[/color]
> >
> >Well they aren't so magic 65 is equal to A and 25 is the range
> >of the Alphabet :-) so the generated string will be between
> >(A-Z)[/color]
>
> Yes, they *ARE* magic.
>
> C does not guarantee ANY of:
>
> <snip>
> The alphabet contains 25 or 26 letters.
> There are no unaccented letters in the character set.
> <snip>[/color]

What do you mean by this, given 5.2.1p3...

Both the basic source and basic execution character sets
shall have the following members: the 26 uppercase letters
of the Latin alphabet
A B C D E F G H I J K L M
N O P Q R S T U V W X Y Z
the 26 lowercase letters of the Latin alphabet
a b c d e f g h i j k l m
n o p q r s t u v w x y z
...

--
Peter

[Emmanuel Delahaye]

Re: strtoint

Profetas wrote on 26/07/04 :
[color=blue]
> My goal was to generate a random string, I knew how to generate random
> numbers, any way here is my solution.
>
> for(i=0; i<16; i++)
> {
> var_ptr[i]=65 + rand()%25;
> }[/color]

Assuming ASCII, you can replace 65 by 'A' and it will work. The trap is
that you have to add a final 0 to make the array of char, a string [1].

A more portable way should be:

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

int main (void)
{
char s[16 + 1];
size_t i;

static char a_alpha[26] = "ABCDEFGHIJKLMN OPQRSTUVWXYZ";

srand ((int) time (NULL));

for (i = 0; i < sizeof s - 1; i++)
{
s[i] = a_alpha[rand () % sizeof a_alpha]; /* assuming A-Z */
}

s[i] = 0;

printf ("s = '%s'\n", s);

return 0;
}

Output:

s = 'NYMLWOBQXZNGHQ IQ'

s = 'LWNWXNLMZIXIBM LF'

---------------------
[1] Maybe it was obvious to you, but in that case, you should have
shown it more clearly.

Additionally, other people, mainly newbies, are reading the newsgroup,
and if they see a code without corrections, they tend to read it as a
valid code. This is why my ethic leads me to avoid to leave bad or
incomplete code without a comment.

--
Emmanuel
The C-FAQ: http://www.eskimo.com/~scs/C-faq/faq.html

"C is a sharp tool"

[Emmanuel Delahaye]

Re: strtoint

Profetas wrote on 26/07/04 :[color=blue][color=green]
>> Well that is not a bad approach. However the magic numbers 65 and 25
>> trouble me.[/color]
>
> Well they aren't so magic 65 is equal to A[/color]

In ASCII only.
[color=blue]
> and 25 is the range
> of the Alphabet :-) so the generated string will be between
> (A-Z)[/color]

Used to be 26 to me, but maybe we don't have the same alphabet (I
learnt recently that some letters don't exist in Italian for
example)...

--
Emmanuel
The C-FAQ: http://www.eskimo.com/~scs/C-faq/faq.html

"C is a sharp tool"

[Emmanuel Delahaye]

Re: strtoint

Old Wolf wrote on 26/07/04 :[color=blue][color=green][color=darkred]
>>> char arr['a','b','c'];[/color]
>>
>> This is not C.[/color]
>
> Actually it is; if the system uses ASCII then it declares an
> array of 99 chars.[/color]

Error MAIN.C 5: Array bounds missing ]

--
Emmanuel
The C-FAQ: http://www.eskimo.com/~scs/C-faq/faq.html

"C is a sharp tool"

[Gordon Burditt]

Re: strtoint

>> C does not guarantee ANY of:[color=blue][color=green]
>>
>> <snip>
>> The alphabet contains 25 or 26 letters.
>> There are no unaccented letters in the character set.
>> <snip>[/color]
>
>What do you mean by this, given 5.2.1p3...
>
> Both the basic source and basic execution character sets
> shall have the following members: the 26 uppercase letters
> of the Latin alphabet
> A B C D E F G H I J K L M
> N O P Q R S T U V W X Y Z
> the 26 lowercase letters of the Latin alphabet
> a b c d e f g h i j k l m
> n o p q r s t u v w x y z
> ...[/color]

I said: C does not guarantee ANY of
.... there are no unaccented letters in the character set.

Since your quote from the standard demonstrates that there
are at least 52 unaccented letters, it proves my point.

Actually, I meant "C does not guarantee that there are no accented
letters in the character set", but with the mistake the result was
still true.

Gordon L. Burditt

[Chris Torek]

Re: strtoint

>> Profetas wrote on 25/07/04 :[color=blue][color=green][color=darkred]
>> > char arr['a','b','c'];[/color][/color][/color]
[color=blue]
>Emmanuel Delahaye <emdel@YOURBRAn oos.fr> wrote:[color=green]
>> This is not C.[/color][/color]

In article <843a4f78.04072 51810.1cd6534e@ posting.google. com>
Old Wolf <oldwolf@inspir e.net.nz> writes:[color=blue]
>Actually it is; if the system uses ASCII then it declares an
>array of 99 chars.[/color]

Even in C99, a constant-expression cannot contain a comma-expression:

[#3] Constant expressions shall not contain assignment,
increment, decrement, function-call, or comma operators,
except when they are contained within the operand of a
sizeof operator.83

I have never understood why comma-expressions are forbidden,
although certainly for the code in ">>>" above, a warning is
quite desirable even in non-Standard modes in which comma-expressions
*are* allowed in constants.
--
In-Real-Life: Chris Torek, Wind River Systems
Salt Lake City, UT, USA (40°39.22'N, 111°50.29'W) +1 801 277 2603
email: forget about it http://web.torek.net/torek/index.html
Reading email is like searching for food in the garbage, thanks to spammers.

[Keith Thompson]

Re: strtoint

Al Bowers <xabowers@rapid sys.com> writes:
[...][color=blue]
> This news group is dedicated to the language as defined by the
> C Standard(ISO/IEC 9899:1999). Again, I point out that in this
> newsgroup, with readers that use various implementations , that
> your assertion that 'A' is value 65 is idiotic.[/color]

No, it's not idiotic. It's merely incorrect.

--
Keith Thompson (The_Other_Keit h) kst-u@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

[Keith Thompson]

Re: strtoint

Chris Torek <nospam@torek.n et> writes:[color=blue][color=green][color=darkred]
> >> Profetas wrote on 25/07/04 :
> >> > char arr['a','b','c'];[/color][/color]
>[color=green]
> >Emmanuel Delahaye <emdel@YOURBRAn oos.fr> wrote:[color=darkred]
> >> This is not C.[/color][/color]
>
> In article <843a4f78.04072 51810.1cd6534e@ posting.google. com>
> Old Wolf <oldwolf@inspir e.net.nz> writes:[color=green]
> >Actually it is; if the system uses ASCII then it declares an
> >array of 99 chars.[/color]
>
> Even in C99, a constant-expression cannot contain a comma-expression:
>
> [#3] Constant expressions shall not contain assignment,
> increment, decrement, function-call, or comma operators,
> except when they are contained within the operand of a
> sizeof operator.83[/color]

Right, but in C99 the expression between the square brackets doesn't
have to be a constant-expression, so
char arr['a','b','c'];
declares a variable length array (even though the length can be
determined at compilation time).
[color=blue]
> I have never understood why comma-expressions are forbidden,
> although certainly for the code in ">>>" above, a warning is
> quite desirable even in non-Standard modes in which comma-expressions
> *are* allowed in constants.[/color]

Probably because a constant-expression with a comma operator most
likely indicates a bug. The left operand of a comma operator is
evaluated only for its side effects, and a constant-expression can't
have side effects.

--
Keith Thompson (The_Other_Keit h) kst-u@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

[Chris Torek]

Re: strtoint

>Chris Torek <nospam@torek.n et> writes:[color=blue][color=green]
>>Even in C99, a constant-expression cannot contain a
>>comma-expression ...[/color][/color]

In article <lnfz7ftfpm.fsf @nuthaus.mib.or g>
Keith Thompson <kst-u@mib.org> writes:[color=blue]
>Right, but in C99 the expression between the square brackets doesn't
>have to be a constant-expression, so
> char arr['a','b','c'];
>declares a variable length array (even though the length can be
>determined at compilation time).[/color]

True, but only if "arr" appears in a context in which VLAs are
allowed. So it is always invalid in C89, and sometimes valid
in C99:

char wrong[1,2]; /* error in both C89 and C99 */
void fn(void) {
char ok_and_VLA[1,2]; /* error in C89, otherwise VLA of size 2 */
...
}

Interestingly, one can test for "VLA-ness" at runtime by applying
the sizeof operator, whose operand *is* evaluated if the operand
is a VLA. I am not quite sure whether this can be used to detect
whether a given C99 compiler treats (1,2) as a constant-expression
in the "ok_and_VLA " case above.
--
In-Real-Life: Chris Torek, Wind River Systems
Salt Lake City, UT, USA (40°39.22'N, 111°50.29'W) +1 801 277 2603
email: forget about it http://web.torek.net/torek/index.html
Reading email is like searching for food in the garbage, thanks to spammers.

[Al Bowers]

Re: strtoint



Chris Torek wrote:[color=blue][color=green][color=darkred]
>>>Profetas wrote on 25/07/04 :
>>>
>>>>char arr['a','b','c'];[/color][/color]
>
>[color=green]
>>Emmanuel Delahaye <emdel@YOURBRAn oos.fr> wrote:
>>[color=darkred]
>>>This is not C.[/color][/color]
>
>
> In article <843a4f78.04072 51810.1cd6534e@ posting.google. com>
> Old Wolf <oldwolf@inspir e.net.nz> writes:
>[color=green]
>>Actually it is; if the system uses ASCII then it declares an
>>array of 99 chars.[/color]
>
>
> Even in C99, a constant-expression cannot contain a comma-expression:
>
> [#3] Constant expressions shall not contain assignment,
> increment, decrement, function-call, or comma operators,
> except when they are contained within the operand of a
> sizeof operator.83
>[/color]

Because of the comma operator, the expression, ('a','b','c') cannot
be a constant expression. However, vla's do not require a constant
expression and in my opinion the non-constant expression would
be nothing other than a poor construct of the array.

In defect report 261:

http://www.open-std.org/jtc1/sc22/wg14/www/docs/dr_261.htm

I quote:

"The Committee also agrees that:

int fla [(0+5)]; // is a normal array, not variably modified
int vla [(0,5)]; // is a variable length array"


--
Al Bowers
Tampa, Fl USA
mailto: xabowers@myrapi dsys.com (remove the x to send email)

http://www.geocities.com/abowers822/