Time stamp in the C programming language

Question

How do I stamp two times t1 and t2 and get the difference in milliseconds in C?

Answer 1

/*
 Returns the current time.
*/

char *time_stamp(){

char *timestamp = (char *)malloc(sizeof(char) * 16);
time_t ltime;
ltime=time(NULL);
struct tm *tm;
tm=localtime(<ime);

sprintf(timestamp,"%04d%02d%02d%02d%02d%02d", tm->tm_year+1900, tm->tm_mon, 
    tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec);
return timestamp;
}


int main(){

printf(" Timestamp: %s\n",time_stamp());
return 0;

}

Output: Timestamp: 20110912130940 // 2011 Sep 12 13:09:40