C truncate HH:MM:SS from ctime value, ctime

Question

I have this unix timestamp which when converted using ctime shows as Thu Mar 26 15:30:26 2007, but I need only Thu Mar 26 2007.

How do I change or truncate to eliminate the time (HH:MM:SS)?

Answer 1

Since you've got a time_t value, you can use localtime() and strftime():

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

int main(void)
{
    time_t t = time(0);
    struct tm *lt = localtime(&t);
    char buffer[20];
    strftime(buffer, sizeof(buffer), "%a %b %d %Y", lt);
    puts(buffer);
    return(0);
}

Alternatively, if you feel you must use ctime(), then:

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

int main(void)
{
    time_t t = time(0);
    char buffer[20];
    char *str = ctime(&t);
    memmove(&buffer[0],  &str[0],  11);
    memmove(&buffer[11], &str[20],  4);
    buffer[15] = '\0';
    puts(buffer);
    return(0);
}

Answer 2

From the manpage of strptime():

The following example demonstrates the use of strptime() and strftime().

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

   int main() {
           struct tm tm;
           char buf[255];

           strptime("2001-11-12 18:31:01", "%Y-%m-%d %H:%M:%S", &tm);
           strftime(buf, sizeof(buf), "%d %b %Y %H:%M", &tm);
           puts(buf);
           return 0;
   }

Adjust to your own needs.