#include <stdio.h>

typedef struct
{
  unsigned int year, month, day, hour, min, sec ;
} date_t1 ;

typedef struct
{
  unsigned short year ;
  unsigned char  month, day ;
  unsigned char  hour, min, sec ;
} date_t2 ;

typedef struct
{
  unsigned short year:12 ;
  unsigned char  month:4 ;
  unsigned char  day:5 ;
  unsigned char  hour:5 ;
  unsigned char  min:6 ;
  unsigned char  sec:6 ;
} date_t3 ;

int main ()
{
  printf ("date_t1 ocupa %ld bytes\n", sizeof (date_t1)) ;
  printf ("date_t2 ocupa %ld bytes\n", sizeof (date_t2)) ;
  printf ("date_t3 ocupa %ld bytes\n", sizeof (date_t3)) ;
}