A quick question

[Christopher Benson-Manica]

Given the following:

char s[15]="Hello, world\n!";

Are all the following guaranteed to produce the same output?

printf( "%s", s );
fprintf( stdout, "%s", s );
fwrite( s, sizeof(char), sizeof(s)/sizeof(char) - 1, stdout );

(It's the last of these that I'm specifically wondering about.)

--
Christopher Benson-Manica | I *should* know what I'm talking about - if I
ataru(at)cybers pace.org | don't, I need to know. Flames welcome.

[Dan Pop]

In <40***********@ earthlink.net> Joe Wright <jo********@ear thlink.net> writes:

Christopher Benson-Manica wrote:

Given the following:

char s[15]="Hello, world\n!";

Are all the following guaranteed to produce the same output?

printf( "%s", s );
fprintf( stdout, "%s", s );
fwrite( s, sizeof(char), sizeof(s)/sizeof(char) - 1, stdout );

(It's the last of these that I'm specifically wondering about.)

Sorry I'm late. It is the last line that is of interest. The first
problem is that 'sizeof s' is of no interest as it might well be 256 or
somesuch.

Please elaborate.

Dan
--
Dan Pop
DESY Zeuthen, RZ group
Email: Da*****@ifh.de

[Dan Pop]

In <bv**********@c hessie.cirr.com > Christopher Benson-Manica <at***@nospam.c yberspace.org> writes:

Given the following:

char s[15]="Hello, world\n!";

Are all the following guaranteed to produce the same output?

printf( "%s", s );
fprintf( stdout, "%s", s );
fwrite( s, sizeof(char), sizeof(s)/sizeof(char) - 1, stdout );

In the abstract machine, all three of them result in fputc being called
15 times, to output the same sequence of characters, to stdout.

Dan
--
Dan Pop
DESY Zeuthen, RZ group
Email: Da*****@ifh.de

[Joe Wright]

Dan Pop wrote:

In <bv**********@c hessie.cirr.com > Christopher Benson-Manica <at***@nospam.c yberspace.org> writes:

Given the following:

char s[15]="Hello, world\n!";

Are all the following guaranteed to produce the same output?

printf( "%s", s );
fprintf( stdout, "%s", s );
fwrite( s, sizeof(char), sizeof(s)/sizeof(char) - 1, stdout );

In the abstract machine, all three of them result in fputc being called
15 times, to output the same sequence of characters, to stdout.

That would be 14 times.
--
Joe Wright http://www.jw-wright.com
"Everything should be made as simple as possible, but not simpler."
--- Albert Einstein ---

[Joe Wright]

Christopher Benson-Manica wrote:

Joe Wright <jo********@ear thlink.net> spoke thus:

fwrite( s, sizeof(char), sizeof(s)/sizeof(char) - 1, stdout );

'sizeof s' is of no interest as it might well be 256 or
somesuch.

Not so, if other replies are to be believed (as well as a great deal
of code produced by better hands than mine). sizeof s yields 15 here,
although I would be grateful if someone would post the portion of the
Standard, if any, which guarantees that.

I don't know where the -1 stuff comes from.

I specifically wished to avoid printing the NUL terminator.

While sizeof s is 15, strlen(s) is 14 (NUL is not included). Your printf
and fprintf examples print 14 characters.
--
Joe Wright http://www.jw-wright.com
"Everything should be made as simple as possible, but not simpler."
--- Albert Einstein ---

[Joe Wright]

Dan Pop wrote:

In <40***********@ earthlink.net> Joe Wright <jo********@ear thlink.net> writes:

Christopher Benson-Manica wrote:

Given the following:

char s[15]="Hello, world\n!";

Are all the following guaranteed to produce the same output?

printf( "%s", s );
fprintf( stdout, "%s", s );
fwrite( s, sizeof(char), sizeof(s)/sizeof(char) - 1, stdout );

(It's the last of these that I'm specifically wondering about.)

Sorry I'm late. It is the last line that is of interest. The first
problem is that 'sizeof s' is of no interest as it might well be 256 or
somesuch.

Please elaborate.

I mean that the length of the string (14) is understood by printf and
fprintf and is returned by strlen(s) in my version of fwrite. The
convolution of 'sizeof s - 1' to achieve 14 is wierd.
--
Joe Wright http://www.jw-wright.com
"Everything should be made as simple as possible, but not simpler."
--- Albert Einstein ---

[Christopher Benson-Manica]

Joe Wright <jo********@ear thlink.net> spoke thus:

While sizeof s is 15, strlen(s) is 14 (NUL is not included). Your printf
and fprintf examples print 14 characters.

And so does the fwrite(), which was the point of the question...

--
Christopher Benson-Manica | I *should* know what I'm talking about - if I
ataru(at)cybers pace.org | don't, I need to know. Flames welcome.

[Joe Wright]

Christopher Benson-Manica wrote:

Joe Wright <jo********@ear thlink.net> spoke thus:

While sizeof s is 15, strlen(s) is 14 (NUL is not included). Your printf
and fprintf examples print 14 characters.

And so does the fwrite(), which was the point of the question...

My point was that strlen(s) is the answer to the question, 'not sizeof
s'. Consider 'char s[100] = "Hello, world!\n";'. sizeof s is 100,
strlen(s) is 14. The example of 'char s[15] = "Hello, world!\n";' is
contrived to define s to hold the 14 character string exactly.
--
Joe Wright http://www.jw-wright.com
"Everything should be made as simple as possible, but not simpler."
--- Albert Einstein ---

[Christopher Benson-Manica]

Joe Wright <jo********@ear thlink.net> spoke thus:

My point was that strlen(s) is the answer to the question, 'not sizeof
s'. Consider 'char s[100] = "Hello, world!\n";'. sizeof s is 100,
strlen(s) is 14. The example of 'char s[15] = "Hello, world!\n";' is
contrived to define s to hold the 14 character string exactly.

Although strlen(s) is the *wrong* answer if you consider 'char
s[14]="Hello, world!\n"', which was being advocated in the recent "[C]
strings question" (or something to that effect) thread. The point of
the question was to determine whether such practice was illegal or
merely morally reprehenisble ;)

--
Christopher Benson-Manica | I *should* know what I'm talking about - if I
ataru(at)cybers pace.org | don't, I need to know. Flames welcome.

[Joe Wright]

Christopher Benson-Manica wrote:

Joe Wright <jo********@ear thlink.net> spoke thus:

My point was that strlen(s) is the answer to the question, 'not sizeof
s'. Consider 'char s[100] = "Hello, world!\n";'. sizeof s is 100,
strlen(s) is 14. The example of 'char s[15] = "Hello, world!\n";' is
contrived to define s to hold the 14 character string exactly.

Although strlen(s) is the *wrong* answer if you consider 'char
s[14]="Hello, world!\n"', which was being advocated in the recent "[C]
strings question" (or something to that effect) thread. The point of
the question was to determine whether such practice was illegal or
merely morally reprehenisble ;)

It is *wrong* because 'char s[14]="Hello, world!\n"' is not a C string.
It seems contrived to make some specious point. I'd say reprehensible.
:-)
--
Joe Wright http://www.jw-wright.com
"Everything should be made as simple as possible, but not simpler."
--- Albert Einstein ---

[Christopher Benson-Manica]

Joe Wright <jo********@ear thlink.net> spoke thus:

It is *wrong* because 'char s[14]="Hello, world!\n"' is not a C string.

I said as much... "but my words like silent raindrops fell" :)

--
Christopher Benson-Manica | I *should* know what I'm talking about - if I
ataru(at)cybers pace.org | don't, I need to know. Flames welcome.