* printf format type, precision...
@ 2004-07-02 22:32 J.
2004-07-02 23:10 ` wwp
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: J. @ 2004-07-02 22:32 UTC (permalink / raw)
To: linux-c-programming
Saturday, July 03 00:18:09
Hello,
I am trying to convert an IP address to it's eq. in base10
[homework]. However the outcome from the formula listed below isn't giving
me the right results. Is this because I'm using the wrong precision type
for the `result' variable ? If that's the case what other precision type
should I use instead ? Right now I can't see the format tree's trhu the
precision forrest anmore .. ehum.
#include <stdio.h>
int main(void) {
int var1 = 192;
int var2 = 168;
int var3 = 1;
int var4 = 10;
long int result = 0;
result = var1 * (256 ^ 3) + var2 * (256 ^ 2) * var3 * 256 + var4;
printf("%ld\n", value);
return 0;
}
Your comments and suggestions will be greatly appreciated..
Thnks..!
J.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: printf format type, precision...
2004-07-02 22:32 printf format type, precision J.
@ 2004-07-02 23:10 ` wwp
2004-07-02 23:29 ` J.
2004-07-02 23:11 ` Glynn Clements
2004-07-02 23:19 ` wwp
2 siblings, 1 reply; 6+ messages in thread
From: wwp @ 2004-07-02 23:10 UTC (permalink / raw)
To: linux-c-programming
Hello J.,
On Sat, 3 Jul 2004 00:32:27 +0200 (CEST) "J." <mailing-lists@xs4all.nl> wrote:
> Saturday, July 03 00:18:09
>
> Hello,
>
> I am trying to convert an IP address to it's eq. in base10
> [homework]. However the outcome from the formula listed below isn't giving
> me the right results. Is this because I'm using the wrong precision type
> for the `result' variable ? If that's the case what other precision type
> should I use instead ? Right now I can't see the format tree's trhu the
> precision forrest anmore .. ehum.
>
> #include <stdio.h>
>
> int main(void) {
> int var1 = 192;
> int var2 = 168;
> int var3 = 1;
> int var4 = 10;
> long int result = 0;
>
> result = var1 * (256 ^ 3) + var2 * (256 ^ 2) * var3 * 256 + var4;
> printf("%ld\n", value);
>
> return 0;
> }
>
> Your comments and suggestions will be greatly appreciated..
You meant:
printf("%ld\n", result);
instead of:
printf("%ld\n", value);
What do you get, what do you expect?
Regards,
--
wwp
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: printf format type, precision...
2004-07-02 22:32 printf format type, precision J.
2004-07-02 23:10 ` wwp
@ 2004-07-02 23:11 ` Glynn Clements
2004-07-02 23:19 ` wwp
2 siblings, 0 replies; 6+ messages in thread
From: Glynn Clements @ 2004-07-02 23:11 UTC (permalink / raw)
To: linux-c-programming
J. wrote:
> I am trying to convert an IP address to it's eq. in base10
> [homework]. However the outcome from the formula listed below isn't giving
> me the right results. Is this because I'm using the wrong precision type
> for the `result' variable ? If that's the case what other precision type
> should I use instead ? Right now I can't see the format tree's trhu the
> precision forrest anmore .. ehum.
>
> #include <stdio.h>
>
> int main(void) {
> int var1 = 192;
> int var2 = 168;
> int var3 = 1;
> int var4 = 10;
> long int result = 0;
>
> result = var1 * (256 ^ 3) + var2 * (256 ^ 2) * var3 * 256 + var4;
> printf("%ld\n", value);
>
> return 0;
> }
>
> Your comments and suggestions will be greatly appreciated..
In C, the ^ operator performs bitwise exclusive-or (XOR), not
exponentiation.
C doesn't have an exponentiation operator, and even if it did, it
wouldn't make sense to use it for powers of two. Use the left shift
operator (<<) instead.
BTW, the result should be unsigned, and displayed with %u, otherwise
addresses where the topmost byte is >= 128 will result in a negative
number.
--
Glynn Clements <glynn.clements@virgin.net>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: printf format type, precision...
2004-07-02 22:32 printf format type, precision J.
2004-07-02 23:10 ` wwp
2004-07-02 23:11 ` Glynn Clements
@ 2004-07-02 23:19 ` wwp
2004-07-02 23:36 ` printf format type, precision... Solved J.
2 siblings, 1 reply; 6+ messages in thread
From: wwp @ 2004-07-02 23:19 UTC (permalink / raw)
To: linux-c-programming; +Cc: mailing-lists
Hello J.,
On Sat, 3 Jul 2004 00:32:27 +0200 (CEST) "J." <mailing-lists@xs4all.nl> wrote:
> Saturday, July 03 00:18:09
>
> Hello,
>
> I am trying to convert an IP address to it's eq. in base10
> [homework]. However the outcome from the formula listed below isn't giving
> me the right results. Is this because I'm using the wrong precision type
> for the `result' variable ? If that's the case what other precision type
> should I use instead ? Right now I can't see the format tree's trhu the
> precision forrest anmore .. ehum.
See if the following gives what you expect. Please not the () around the <<
operation, try w/o them (you'll see the difference about operator precedence).
#include <stdio.h>
int main(void) {
int var1 = 192;
int var2 = 168;
int var3 = 1;
int var4 = 10;
long unsigned int result = 0;
result = (var1 << 24) + (var2 << 16) + (var3 << 8) + var4;
printf("%lu %0lx\n", result, result);
return 0;
}
Regards,
--
wwp
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: printf format type, precision...
2004-07-02 23:10 ` wwp
@ 2004-07-02 23:29 ` J.
0 siblings, 0 replies; 6+ messages in thread
From: J. @ 2004-07-02 23:29 UTC (permalink / raw)
To: linux-c-programming
On Sat, 3 Jul 2004, wwp wrote:
> Hello J.,
Hello wwp ;-)
> On Sat, 3 Jul 2004 00:32:27 +0200 (CEST) "J." <mailing-lists@xs4all.nl> wrote:
<CUT>... question/code </CUT>
> > Your comments and suggestions will be greatly appreciated..
>
> You meant:
> printf("%ld\n", result);
> instead of:
> printf("%ld\n", value);
I am sorry, that was a sloppy mistake from my side while cutting and
pasting the code into the message and making sure the code didn't got
garbled...
But I am affraid my problem/point still stands, it still prints
the incorrect value.
> What do you get, what do you expect?
>
> Regards,
>
> --
> wwp
Thnkx.. !
J.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: printf format type, precision... Solved..
2004-07-02 23:19 ` wwp
@ 2004-07-02 23:36 ` J.
0 siblings, 0 replies; 6+ messages in thread
From: J. @ 2004-07-02 23:36 UTC (permalink / raw)
To: linux-c-programming
Saturday, July 03 01:32:25
Ohh.. super guys.. That solved it. Thankx for the complete answers and
especially the explanation behind it and how to improve...
I am seeing the operator tree's in the c wood again ;-)
Thankx again.. !
J.
^ permalink raw reply [flat|nested] 6+ messages in thread
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2004-07-02 22:32 printf format type, precision J.
2004-07-02 23:10 ` wwp
2004-07-02 23:29 ` J.
2004-07-02 23:11 ` Glynn Clements
2004-07-02 23:19 ` wwp
2004-07-02 23:36 ` printf format type, precision... Solved J.
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