YMD
jd2ymd(JD jd)
{
YMD ymd;
double j;
double x;
int y, m, d;
j = jdGetDay(jd);
j2gcal(&y, &m, &d, j);
ymdSetYear(ymd, y);
ymdSetMonth(ymd, m);
ymdSetDay(ymd, (double)d);
x = (j - floor(j));
/*
** we do this next step because the rounding of j in j2gcal()
** either credits or debits us with 12 hours
*/
if (x < 0.5) {
x += 0.5;
} else {
x -= 0.5;
}
ymdIncDay(ymd, x);
/* pick up the hours, minutes, and seconds */
ymd.hms = jd.hms;
return(ymd);
}
YMD
ymd2ymd(YMD ymd)
{
double j; /* julian day number */
double x;
int y, m, d;
j = ymd2j(ymd);
j2gcal(&y, &m, &d, j);
ymdSetYear(ymd, y);
ymdSetMonth(ymd, m);
ymdSetDay(ymd, d);
x = j - floor(j);
/*
** we do this next step because the rounding of j in j2gcal()
** either credits or debits us with 12 hours
*/
if (x < 0.5) {
x += 0.5;
} else {
x -= 0.5;
}
/* promote the hours */
x = (x - floor(x)) * 24.0;
ymdSetHours(ymd, floor(x));
/* promote the minutes */
x = (x - floor(x)) * 60.0;
ymdSetMinutes(ymd, floor(x));
/* promote the seconds */
x = (x - floor(x)) * 60.0;
ymdSetSeconds(ymd, x);
return(ymd);
}
