int64 from int 32

[Peerless]

Hi,
For some reason the below code doesnt produce results as i expect.

#include<stdio. h>

int main()
{

int hi=0xff;
int low=0xee;
long long big ;
big = ((long long) hi ) << 32 | low;

printf("%16x \n ",big);

}

I am lost trying to figure out the mistake i am making.Can you help me
out.Is it compiler dependent?

Deepak

[Nate Eldredge]

Peerless <pe************ *@gmail.comwrit es:

Hi,
For some reason the below code doesnt produce results as i expect.

#include<stdio. h>

int main()
{

int hi=0xff;
int low=0xee;
long long big ;
big = ((long long) hi ) << 32 | low;

printf("%16x \n ",big);

}

I am lost trying to figure out the mistake i am making.Can you help me
out.Is it compiler dependent?

The %x specifier for printf expects an unsigned argument, not a long
long. Using %llx will use an unsigned long long. So you might want

unsigned long long big;
big = ((unsigned long long)hi) << 32 | low;
printf("%16llx\ n", big);

This conforms to the C99 standard, by the way, so it shouldn't be
compiler dependent.

[jameskuyper]

Peerless wrote:

Hi,
For some reason the below code doesnt produce results as i expect.

#include<stdio. h>

int main()
{

int hi=0xff;
int low=0xee;
long long big ;
big = ((long long) hi ) << 32 | low;

printf("%16x \n ",big);

}

I am lost trying to figure out the mistake i am making.Can you help me
out.Is it compiler dependent?

Support for 'long long' is compiler dependent, because not all
compilers conform to the C99 standard in that regard yet. However, if
that had been your problem, your code would never have compiled.

I strongly recommend using unsigned types whenever you are performing
shifts or bit-masking operations. However, for the particular values
involved in your program, that's not a problem.

What is a problem is that 'big' is a "long long", and you're using
%16x as your format code, which requires an "unsigned int" argument.
After changing everything to an unsigned type, you should use
"%16llx", which expects an "unsigned long long" argument.

[Keith Thompson]

Peerless <pe************ *@gmail.comwrit es:

For some reason the below code doesnt produce results as i expect.

#include<stdio. h>

int main()
{

int hi=0xff;
int low=0xee;
long long big ;
big = ((long long) hi ) << 32 | low;

printf("%16x \n ",big);

}

I am lost trying to figure out the mistake i am making.Can you help me
out.Is it compiler dependent?

"%16x" expects an argument of type unsigned int. You're giving it an
argument of type long long. Use "%16llx". (It's not certain that
your runtime library will support this.)

Actually, I'd probably use "%016llx" to get the leading zeros.

Also, why do you have spaces before and after the "\n"?

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
Nokia
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

[Keith Thompson]

Nate Eldredge <na**@vulcan.la nwrites:
[...]

The %x specifier for printf expects an unsigned argument, not a long
long. Using %llx will use an unsigned long long. So you might want

unsigned long long big;
big = ((unsigned long long)hi) << 32 | low;
printf("%16llx\ n", big);

This conforms to the C99 standard, by the way, so it shouldn't be
compiler dependent.

Um, are you suggesting that all compilers conform to the C99 standard?

Quibble: It's the runtime library, not the compiler, that implements
printf and the "%llx" format. Both the library and the compiler are
part of the implementation.
--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
Nokia
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

[Peter Nilsson]

Keith Thompson <[e-mail] rote:

Nate Eldredge <[e-mail] nwrites:

...
unsigned long long big;
big = ((unsigned long long)hi) << 32 | low;
printf("%16llx\ n", big);

This conforms to the C99 standard, by the way, so
it shouldn't be compiler dependent. *

Um, are you suggesting that all compilers conform to
the C99 standard?

Quibble: It's the runtime library, not the compiler,
that implements printf and the "%llx" format. *Both
the library and the compiler are part of the
implementation.

Do you know of any packaged C90 implementations that
support long long but don't support ll? It's been a
well over a decade since I've seen a C90 implementation
use L as the length specifier for long long.

--
Peter

[Keith Thompson]

Peter Nilsson <ai***@acay.com .auwrites:

Keith Thompson <[e-mail] rote:

>Nate Eldredge <[e-mail] nwrites:

...
unsigned long long big;
big = ((unsigned long long)hi) << 32 | low;
printf("%16llx\ n", big);

This conforms to the C99 standard, by the way, so
it shouldn't be compiler dependent. *

Um, are you suggesting that all compilers conform to
the C99 standard?

Quibble: It's the runtime library, not the compiler,
that implements printf and the "%llx" format. *Both
the library and the compiler are part of the
implementation .

Do you know of any packaged C90 implementations that
support long long but don't support ll? It's been a
well over a decade since I've seen a C90 implementation
use L as the length specifier for long long.

Packaged? No. But gcc, for example, is just a compiler; it isn't
bundled with a runtime library. It uses whatever C runtime library is
available on the platform. *If* there are still runtime libraries
that doesn't support "%llx" (perhaps because the don't support long
long at all), and if gcc is available on such sytems, then there are C
implementations that support long long but not "%llx".

I'm sure there have been such systems in the past. I couldn't tell
you which systems they are, and I don't know whether they're still in
sufficiently widespread use to be a significant concern.

gcc may not be the only example of this.

Bottom line: Check this before depending on it.

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
Nokia
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

[jacob navia]

Peerless wrote:

Hi,
For some reason the below code doesnt produce results as i expect.

#include<stdio. h>

int main()
{

int hi=0xff;
int low=0xee;
long long big ;
big = ((long long) hi ) << 32 | low;

printf("%16x \n ",big);

}

I am lost trying to figure out the mistake i am making.Can you help me
out.Is it compiler dependent?

Deepak

Using the lcc-win compiler I obtain:
d:\lcc\mc74\tes t>lc tll.c
Warning tll.c: 11 printf argument mismatch for format x. Expected int
got long long
0 errors, 1 warning

It helps to get a compiler with good warnings.
--
jacob navia
jacob at jacob point remcomp point fr
logiciels/informatique
http://www.cs.virginia.edu/~lcc-win32

[Martien Verbruggen]

On Wed, 12 Nov 2008 23:12:18 +0100,
jacob navia <ja***@nospam.c omwrote:

Peerless wrote:

>Hi,
For some reason the below code doesnt produce results as i expect.

#include<stdio .h>

int main()
{

int hi=0xff;
int low=0xee;
long long big ;
big = ((long long) hi ) << 32 | low;

printf("%16x \n ",big);

}

I am lost trying to figure out the mistake i am making.Can you help me
out.Is it compiler dependent?

Deepak

Using the lcc-win compiler I obtain:
d:\lcc\mc74\tes t>lc tll.c
Warning tll.c: 11 printf argument mismatch for format x. Expected int
got long long

Isn't the compiler supposed to expect an unsigned int here, instead of
an int?

0 errors, 1 warning

It helps to get a compiler with good warnings.

FWIW, gcc also warns for this, but it claims to be expecting an
unsigned int.

Martien
--
|
Martien Verbruggen | Failure is not an option. It comes bundled
| with your Microsoft product.
|

[Joe Wright]

Peerless wrote:

Hi,
For some reason the below code doesnt produce results as i expect.

#include<stdio. h>

int main()
{

int hi=0xff;
int low=0xee;
long long big ;
big = ((long long) hi ) << 32 | low;

printf("%16x \n ",big);

}

I am lost trying to figure out the mistake i am making.Can you help me
out.Is it compiler dependent?

Deepak

What did you expect? Try this.

#include <stdio.h>

int main(void)
{
int hi = 0xff;
int low = 0xee;
long long big;
big = ((long long)hi) << 32 | low;
printf("%016Lx\ n", big);
return 0;
}

--
Joe Wright
"Everything should be made as simple as possible, but not simpler."
--- Albert Einstein ---