Double printf format...

[naunetr]

in program below

#include <stdio.h>
int main()
{
int id = 123, io = 0123, ih = 0x123;
long ld = 1234567L, lo = 01234567l, lh = 0X1234567L;
float f = 123.456f;
double d = 01234.56789L;

printf("id = %d\t%o\t%x\nio = %d\t%o\t%x\nih = %d\t%O\t%X\n",
id, id, id, io, io, io, ih, ih, ih);
printf("ld = %ld\t%lo\t%lx\n lo = %ld\t%lo\t%lx\n lh = %ld\t%lo\t%l\n" ,
ld, ld, ld, lo, lo, lo, lh, lh, lh);
printf("f = %lf\t%le\t%lg\n d = %lf\t%lE\t%lG\n ", f, f, f, d, d, d);
return 0;
}

the output got is:
id = 123 173 7b
io = 83 123 53
ih = 291 %O 123
ld = 1234567 4553207 12d687
lo = 342391 1234567 53977
lh = 19088743 110642547 1234567
f = 123.456001 1.234560e+02 123.456
d = 1234.567890 1.234568E+03 1234.57

why is there a %O in line 3 instead of octal o/p expected?
and in line for d the last o/p is 1234.57. but %g is either %lf or %le
right? so if it is %lf then why is it 1234.57 instead of 1234.56789?

thanks

[santosh]

naunetr wrote:

in program below

#include <stdio.h>
int main()
{
int id = 123, io = 0123, ih = 0x123;
long ld = 1234567L, lo = 01234567l, lh = 0X1234567L;
float f = 123.456f;
double d = 01234.56789L;

printf("id = %d\t%o\t%x\nio = %d\t%o\t%x\nih = %d\t%O\t%X\n",
id, id, id, io, io, io, ih, ih, ih);
printf("ld = %ld\t%lo\t%lx\n lo = %ld\t%lo\t%lx\n lh =
%ld\t%lo\t%l\n" ,
ld, ld, ld, lo, lo, lo, lh, lh, lh);
printf("f = %lf\t%le\t%lg\n d = %lf\t%lE\t%lG\n ", f, f, f, d, d,
d); return 0;
}

the output got is:
id = 123 173 7b
io = 83 123 53
ih = 291 %O 123
ld = 1234567 4553207 12d687
lo = 342391 1234567 53977
lh = 19088743 110642547 1234567
f = 123.456001 1.234560e+02 123.456
d = 1234.567890 1.234568E+03 1234.57

why is there a %O in line 3 instead of octal o/p expected?

The format specifier for octal output is %o, not %O. In C case is
important.

and in line for d the last o/p is 1234.57. but %g is either %lf or %le
right? so if it is %lf then why is it 1234.57 instead of 1234.56789?

I think that's a precision issue.

[Kenneth Brody]

naunetr wrote:
[...]

why is there a %O in line 3 instead of octal o/p expected?

Because you put it there. The relevant fragment of the format string is
ih = %d\t%O\t%X\n

Notice the %O in the string above? There is no %O conversion specifier,
and the "octal" conversion specifier is %o

thanks Lew. is there a specifier which will put a 0 in front off the octal
number? like 0x for %#x?

What about "0%o" and "0x%x"?

[...]

--
+-------------------------+--------------------+-----------------------+
| Kenneth J. Brody | www.hvcomputer.com | #include |
| kenbrody/at\spamcop.net | www.fptech.com | <std_disclaimer .h|
+-------------------------+--------------------+-----------------------+
Don't e-mail me at: <mailto:Th***** ********@gmail. com>

[Walter Roberson]

In article <fr**********@r egistered.motza rella.org>,
naunetr <wi************ @roadtonowhere. invalidwrote:

>thanks Lew. is there a specifier which will put a 0 in front off the octal
number? like 0x for %#x?

%#o

C89 4.9.6.1 The fprintf Function

# The result is to be converted to an "alternate form." For o
conversion, it increases the precision to force the first digit
of the result to be a zero. For x (or X) conversion, a
nonzero result will have 0x (or 0X) prefixed to it. [...]

>sorry got it confused with scanf! but why is there a %F too? shouldn't %f
be enough?

C89 does not have %F (but does have %E and %G). %E and %G use a
capital E for the exponent signifier instead of a lower-case e
but are otherwise the same as %e and %g respectively.
--
"The quirks and arbitrariness we observe force us to the
conclusion that ours is not the only universe." -- Walter Kistler

[naunetr]

On Thu, 13 Mar 2008 19:16:27 +0000, ro******@ibd.nr c-cnrc.gc.ca (Walter
Roberson) wrote:

On Thu, 13 Mar 2008 19:16:27 +0000, ro******@ibd.nr c-cnrc.gc.ca (Walter
Roberson) wrote:

In article <fr**********@r egistered.motza rella.org>, naunetr
<wi************ @roadtonowhere. invalidwrote:

>>thanks Lew. is there a specifier which will put a 0 in front off the
octal number? like 0x for %#x?

%#o

oops! thought that works only for hex specifier %x.

C89 4.9.6.1 The fprintf Function

# The result is to be converted to an "alternate form." For o
conversion, it increases the precision to force the first digit of
the result to be a zero. For x (or X) conversion, a nonzero result
will have 0x (or 0X) prefixed to it. [...]

>>sorry got it confused with scanf! but why is there a %F too? shouldn't
%f be enough?

C89 does not have %F (but does have %E and %G). %E and %G use a capital
E for the exponent signifier instead of a lower-case e but are otherwise
the same as %e and %g respectively.

thanks Walter. by "C89" you mean ANSI C yes?

[Richard Heathfield]

naunetr said:

On Thu, 13 Mar 2008 19:16:27 +0000, ro******@ibd.nr c-cnrc.gc.ca (Walter
Roberson) wrote:

<snip>

>C89 does not have %F (but does have %E and %G). %E and %G use a capital
E for the exponent signifier instead of a lower-case e but are otherwise
the same as %e and %g respectively.

thanks Walter. by "C89" you mean ANSI C yes?

Almost certainly it's the other way around - that is, by "ANSI C" you mean
C89.

Quick history for you:

dawnatime: R invents C.
dawnatime + a bit: K says "that's cool, let's do a book on it".
1978: K&R published.
1980s: ANSI undertake a standardisation process which culminates in:
1988: K&R2 (based on draft-proposed ANSI C) published.
1989: ANSI formally standardises C (this is C89, which is what you've got)
1990: ISO adopts the ANSI C Standard internationally (C90)
1999: ISO formally re-standardises C (C99)
2000: ANSI adopts C99
1999-2008: Almost the entire universe ignores C99 completely.

--
Richard Heathfield <http://www.cpax.org.uk >
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999

[Ben Bacarisse]

Richard Heathfield <rj*@see.sig.in validwrites:

Quick history for you:

<snip history>

1999-2008: Almost the entire universe ignores C99 completely.

This reflects your personal opinion more accurately than it describes
the truth. It *is* true, of course, but uninterestingly true since
"almost the entire universe ignores X completely" is true for a very
large set of Xs -- including C90!

--
Ben.

[Richard Heathfield]

Ben Bacarisse said:

Richard Heathfield <rj*@see.sig.in validwrites:

>Quick history for you:

<snip history>

>1999-2008: Almost the entire universe ignores C99 completely.

This reflects your personal opinion more accurately than it describes
the truth.

Well, actually it reflects my personal understanding of the truth. The only
validated C99 compilers I know about are:

EDG (Pentium PIII, Linux 7.x series)
IBM XL (IBM POWER PC_970, AIX 5.3h)
IBM Visual Age (IBM PowerPC systems w/ CHRP system architecture, AIX 5L for
POWER, Version 5.2)
LMPCC C99 Compiler for Linux / PowerPC (Motorola PowerPC MPC7455, Terrasoft
Solutions, Yellow Dog Linux 3.0)
Sun Studio 9 (SPARC Ultra/Intel x86/AMD 64, Solaris 10)

(Some of these depend on the validated C99-conforming Dinkum Unabridged
Library.)

Data source: http://www.peren.com/pages/cvsa_isocvpl.htm
I don't have time to research into how many C90-conforming compilers there
are, but ISTR that there are a hundred or so. Does anyone have any better
data?
--
Richard Heathfield <http://www.cpax.org.uk >
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999

[Richard Tobin]

In article <EO************ *************** ***@bt.com>,
Richard Heathfield <rj*@see.sig.in validwrote:

>>1999-2008: Almost the entire universe ignores C99 completely.

>This reflects your personal opinion more accurately than it describes
the truth.

>Well, actually it reflects my personal understanding of the truth. The only
validated C99 compilers I know about are:

The absence of validated C99 compilers doesn't mean that the universe
is completely ignoring C99. For example, I can use inline functions
or VLAs with fair confidence that they will be available, and
sufficiently compatible, on all the systems I care about. I don't
think this would be true without the existence of C99.

-- Richard

--
:wq

[Richard Heathfield]

Richard Tobin said:

<snip>

The absence of validated C99 compilers doesn't mean that the universe
is completely ignoring C99. For example, I can use inline functions
or VLAs with fair confidence that they will be available, and
sufficiently compatible, on all the systems I care about. I don't
think this would be true without the existence of C99.

Understood, but the difficulty is in identifying which features of C99 can
be used "portably". We sure could use a central reference, listing C99
features down the left, compilers across the top, and ticks in the boxes
where the feature has been implemented according to C99 semantics. That
way, maybe people could start to use C99 features with some degree of
confidence that they will be portable to "all the systems I care about",
for various values of "I".

--
Richard Heathfield <http://www.cpax.org.uk >
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999