How to print time in format: 2009‐08‐10 18:17:54.811

Question

What\'s the best method to print out time in C in the format 2009‐08‐10 
18:17:54.811?

Answer 1

time.h defines a strftime function which can give you a textual representation of a time_t using something like:

#include 
#include 
int main (void) {
    char buff[100];
    time_t now = time (0);
    strftime (buff, 100, "%Y-%m-%d %H:%M:%S.000", localtime (&now));
    printf ("%s\n", buff);
    return 0;
}

but that won't give you sub-second resolution since that's not available from a time_t. It outputs:

2010-09-09 10:08:34.000

If you're really constrained by the specs and do not want the space between the day and hour, just remove it from the format string.