simple question (itoa, localtime)

Raskolnikow

Hi!

I have a very simple problem with itoa() or the localtime(...).
Sorry, if it is too simple, I don't have a proper example.
Please have a look at the comments.

struct tm *systime;
time_t currentTime;
char day[2];
char month[2];
char currentDate[6];

main(int argc, char **argv)
{
time(&currentTime);
systime = localtime(&currentTime);

itoa(systime->tm_mday, day, 10);
itoa(systime->tm_mon, month, 10);
printf("day = %s month = %s\n", day, month);
/** QUESTION: why is [day] not the current day but something arbitrary **/

strcat(currentDate, day);
strcat(currentDate, ".");
strcat(currentDate, month);
strcat(currentDate, ".");
/** QUESTION: Is there something simpler than that to concatenate strings ?
**/
<snip>

Thank you !

Brad

Nov 13 '05 #1

code_wrong

bear in mind I am no expert
comments inline

"Raskolnikow" <raskolnikow@freesurf.ch> wrote in message
news:bfkjlu$fsv1n$1@ID-126543.news.uni-berlin.de...[color=blue]
> Hi!
>
> I have a very simple problem with itoa() or the localtime(...).
> Sorry, if it is too simple, I don't have a proper example.
> Please have a look at the comments.
>
> struct tm *systime;
> time_t currentTime;[/color]

You have not allowed for the string terminating null character
try char day[3];
[color=blue]
> char day[2];[/color]

same here
[color=blue]
> char month[2];[/color]

[color=blue]
> char currentDate[6];
>
> main(int argc, char **argv)
> {
> time(&currentTime);
> systime = localtime(&currentTime);
>[/color]

You are aware that itoa() is not standard ANSI C and is therefore off topic
for this newsgroup
[color=blue]
> itoa(systime->tm_mday, day, 10);
> itoa(systime->tm_mon, month, 10);[/color]

You could use strftime() to format a string in a multitude of ways for
displaying
[color=blue]
> printf("day = %s month = %s\n", day, month);
> /** QUESTION: why is [day] not the current day but something arbitrary **/[/color]

not enough space allocated for null terminated string as stated above
[color=blue]
>
> strcat(currentDate, day);
> strcat(currentDate, ".");
> strcat(currentDate, month);
> strcat(currentDate, ".");
> /** QUESTION: Is there something simpler than that to concatenate strings[/color]
?[color=blue]
> **/[/color]

yes strftime() for one way

hth
cw

Nov 13 '05 #2

Martin Ambuhl

"Raskolnikow" <raskolnikow@freesurf.ch> wrote (22 Jul 2003) in
news:bfkjlu$fsv1n$1@ID-126543.news.uni-berlin.de / comp.lang.c:
[color=blue]
> Hi!
>
> I have a very simple problem with itoa() or the localtime(...).
> Sorry, if it is too simple, I don't have a proper example.
> Please have a look at the comments.
>[/color]

Missing headers...
[color=blue]
> struct tm *systime;
> time_t currentTime;
> char day[2];
> char month[2];
> char currentDate[6];[/color]

All the above are too small.[color=blue]
>
> main(int argc, char **argv)
> {
> time(&currentTime);
> systime = localtime(&currentTime);
>
> itoa(systime->tm_mday, day, 10);
> itoa(systime->tm_mon, month, 10);
> printf("day = %s month = %s\n", day, month);
> /** QUESTION: why is [day] not the current day but something
> arbitrary **/[/color]

Your clock is set incorrectly.[color=blue]
>
> strcat(currentDate, day);
> strcat(currentDate, ".");
> strcat(currentDate, month);
> strcat(currentDate, ".");
> /** QUESTION: Is there something simpler than that to concatenate
> strings ? **/
> <snip>[/color]

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <time.h>

int main(void)
{
struct tm *systime;
time_t currentTime;
char currentDate[7];

time(&currentTime);
systime = localtime(&currentTime);

printf("day = %d month = %d\n", systime->tm_mday,
1 + systime->tm_mon);
sprintf(currentDate, "%d.%d", systime->tm_mday,
1 + systime->tm_mon);
puts(currentDate);

return 0;
}

What was your question?


--
Martin Ambuhl
Returning soon to the
Fourth Largest City in America

Nov 13 '05 #3