time_t time(time_t *Decalage);
#include <stdio.h>
#include <time.h>
time_t Date;
struct tm *TM;
...
Date=time(NULL);
TM=localtime(&Date);
printf("Le %d/%hd/%hd à %hd:%hd:%hd\n", TM->tm_mday, TM->tm_mon, TM->tm_year, TM->tm_hour, TM->tm_min, TM->tm_sec);