formatting strings

[Rick]

Hi,

Other than "sprintf", is there some way we can easily format a string
composed of, say, integers? I know this might become off topic but I'm
using (an old version of) avr-gcc which does not support sprintf and I
need to patch up a string with a few integers and I dont want to do 10
strcat()'s.

I have a struct containing 3 ints (a struct representing time) and I
need to print the "hour" "minute" and "second" fields as: hh:mm:ss. Is
that possible without a combination of strcats and strcpys. Thanks

Rick

[Eric Sosman]

Rick wrote:

Hi,

Other than "sprintf", is there some way we can easily format a string
composed of, say, integers? I know this might become off topic but I'm
using (an old version of) avr-gcc which does not support sprintf and I
need to patch up a string with a few integers and I dont want to do 10
strcat()'s.

I have a struct containing 3 ints (a struct representing time) and I
need to print the "hour" "minute" and "second" fields as: hh:mm:ss. Is
that possible without a combination of strcats and strcpys. Thanks

Incoming values assumed sensible:

char result[sizeof "hh:mm:ss"];
char *p = result;
*p++ = '0' + hh / 10;
*p++ = '0' + hh % 10;
*p++ = ':';
*p++ = '0' + mm / 10;
*p++ = '0' + mm % 10;
*p++ = ':';
*p++ = '0' + ss / 10;
*p++ = '0' + ss % 10;
*p = '\0';

The `p' variable could be eliminated if desired.

--
Er*********@sun.com

[Dan Pop]

In <3f********@clarion.carno.net.au> Rick <rrquick@nospam-com> writes:

Other than "sprintf", is there some way we can easily format a string
composed of, say, integers?
Integers are very easy to convert to strings.
I know this might become off topic but I'm
using (an old version of) avr-gcc which does not support sprintf and I
need to patch up a string with a few integers and I dont want to do 10
strcat()'s.
You don't do that with strcat, you simply put each digit at its place
in the string.
I have a struct containing 3 ints (a struct representing time) and I
need to print the "hour" "minute" and "second" fields as: hh:mm:ss. Is
that possible without a combination of strcats and strcpys. Thanks

Of course it's possible, it's a matter of *trivial* arithmetic:

char timestr[9];
timestr[0] = '0' + hour / 10;
timestr[1] = '0' + hour % 10;
timestr[2] = ':';
...
timestr[8] = 0;

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

[David Resnick]

Rick <rrquick@nospam-com> wrote in message news:<3f********@clarion.carno.net.au>...

Hi,

Other than "sprintf", is there some way we can easily format a string
composed of, say, integers? I know this might become off topic but I'm
using (an old version of) avr-gcc which does not support sprintf and I
need to patch up a string with a few integers and I dont want to do 10
strcat()'s.

I have a struct containing 3 ints (a struct representing time) and I
need to print the "hour" "minute" and "second" fields as: hh:mm:ss. Is
that possible without a combination of strcats and strcpys. Thanks

Rick

#include <stdio.h>

void format_hms(int hour, int minute, int second, char *buf)
{
buf[0] = hour/10 + '0';
buf[1] = hour%10 + '0';
buf[2] = ':';
buf[3] = minute/10 + '0';
buf[4] = minute%10 + '0';
buf[5] = ':';
buf[6] = second/10 + '0';
buf[7] = second%10 + '0';
buf[8] = '\0';
}
int main(void)
{
char buf[9];
format_hms(10,20,30,buf);
printf("%s\n", buf);
return 0;
}

Eliminating the code duplication, adding error checking, etc would
improve this, but it is a rough idea of something that works.

[Rick]

Thanks Eric.. just wondering.. what does '0' + hh do? Will it convert
the integer into ascii? Neat :)

Rick

Eric Sosman wrote:

Rick wrote:

Hi,

Other than "sprintf", is there some way we can easily format a string
composed of, say, integers? I know this might become off topic but I'm
using (an old version of) avr-gcc which does not support sprintf and I
need to patch up a string with a few integers and I dont want to do 10
strcat()'s.

I have a struct containing 3 ints (a struct representing time) and I
need to print the "hour" "minute" and "second" fields as: hh:mm:ss. Is
that possible without a combination of strcats and strcpys. Thanks

Incoming values assumed sensible:

char result[sizeof "hh:mm:ss"];
char *p = result;
*p++ = '0' + hh / 10;
*p++ = '0' + hh % 10;
*p++ = ':';
*p++ = '0' + mm / 10;
*p++ = '0' + mm % 10;
*p++ = ':';
*p++ = '0' + ss / 10;
*p++ = '0' + ss % 10;
*p = '\0';

The `p' variable could be eliminated if desired.

[Joona I Palaste]

Rick <rrquick@nospam-com> scribbled the following:

Thanks Eric.. just wondering.. what does '0' + hh do? Will it convert
the integer into ascii? Neat :)

No. If hh is in the range [0, 9] it will produce the corresponding
character glyph in whatever character set the implementation is using.
This can be ASCII or some other set.

--
/-- Joona Palaste (pa*****@cc.helsinki.fi) ------------- Finland --------\
\-- http://www.helsinki.fi/~palaste --------------------- rules! --------/
"To know me IS to love me."
- JIPsoft

[Dan Pop]

In <bm**********@oravannahka.helsinki.fi> Joona I Palaste <pa*****@cc.helsinki.fi> writes:

Rick <rrquick@nospam-com> scribbled the following:

Thanks Eric.. just wondering.. what does '0' + hh do? Will it convert
the integer into ascii? Neat :)

No. If hh is in the range [0, 9] it will produce the corresponding
character glyph in whatever character set the implementation is using.

Wrong! It will produce the corresponding character *code*. You need to
output this code to the right kind of device in order to get a glyph.

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

[Joona I Palaste]

Dan Pop <Da*****@cern.ch> scribbled the following:

In <bm**********@oravannahka.helsinki.fi> Joona I Palaste <pa*****@cc.helsinki.fi> writes:

Rick <rrquick@nospam-com> scribbled the following:

Thanks Eric.. just wondering.. what does '0' + hh do? Will it convert
the integer into ascii? Neat :)
No. If hh is in the range [0, 9] it will produce the corresponding
character glyph in whatever character set the implementation is using.

Wrong! It will produce the corresponding character *code*. You need to
output this code to the right kind of device in order to get a glyph.

You have to very pedantic to make that kind of argument. But I suppose
that if we get pedantic enough, you are absolutely correct.

--
/-- Joona Palaste (pa*****@cc.helsinki.fi) ------------- Finland --------\
\-- http://www.helsinki.fi/~palaste --------------------- rules! --------/
"You could take his life and..."
- Mirja Tolsa

[Irrwahn Grausewitz]

Joona I Palaste <pa*****@cc.helsinki.fi> wrote:

Dan Pop <Da*****@cern.ch> scribbled the following:

In <bm**********@oravannahka.helsinki.fi> Joona I Palaste <pa*****@cc.helsinki.fi> writes: <snip>

No. If hh is in the range [0, 9] it will produce the corresponding
character glyph in whatever character set the implementation is using.

Wrong! It will produce the corresponding character *code*. You need to
output this code to the right kind of device in order to get a glyph.

You have to very pedantic to make that kind of argument. But I suppose
that if we get pedantic enough, you are absolutely correct.

Huh?!? He's not correct if we aren't pedantic enough? ;-)

--
Irrwahn
(ir*******@freenet.de)

[Jeremy Yallop]

Irrwahn Grausewitz wrote:

Joona I Palaste <pa*****@cc.helsinki.fi> wrote:

Dan Pop <Da*****@cern.ch> scribbled the following:

In <bm**********@oravannahka.helsinki.fi> Joona I Palaste <pa*****@cc.helsinki.fi> writes:<snip>No. If hh is in the range [0, 9] it will produce the corresponding
character glyph in whatever character set the implementation is using.

Wrong! It will produce the corresponding character *code*. You need to
output this code to the right kind of device in order to get a glyph.

You have to very pedantic to make that kind of argument. But I suppose
that if we get pedantic enough, you are absolutely correct.

Huh?!? He's not correct if we aren't pedantic enough? ;-)

Er, a => b does not imply !a => !b.

Jeremy.

[Irrwahn Grausewitz]

Jeremy Yallop <je****@jdyallop.freeserve.co.uk> wrote:

Irrwahn Grausewitz wrote:

Joona I Palaste <pa*****@cc.helsinki.fi> wrote:

Dan Pop <Da*****@cern.ch> scribbled the following: <snip> Wrong! It will produce the corresponding character *code*. You need to
output this code to the right kind of device in order to get a glyph.

You have to very pedantic to make that kind of argument. But I suppose
that if we get pedantic enough, you are absolutely correct.

Huh?!? He's not correct if we aren't pedantic enough? ;-)

Er, a => b does not imply !a => !b.

Hm, right. But still then, I miss Joona's point.
Maybe he made a joke after all. ;-)

--
Irrwahn
(ir*******@freenet.de)