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

 

[code_wrong]

bear in mind I am no expert
comments inline

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;

You have not allowed for the string terminating null character
try char day[3];

char day[2];

same here

char month[2];

char currentDate[6];

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

You are aware that itoa() is not standard ANSI C and is therefore off topic
for this newsgroup

itoa(systime->tm_mday, day, 10);
itoa(systime->tm_mon, month, 10);

You could use strftime() to format a string in a multitude of ways for
displaying

printf("day = %s month = %s\n", day, month);
/** QUESTION: why is [day] not the current day but something arbitrary **/

not enough space allocated for null terminated string as stated above

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

yes strftime() for one way

hth
cw

 

[Martin Ambuhl]

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.

Missing headers...

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

All the above are too small.

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 **/

Your clock is set incorrectly.

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

#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?