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);
}
int main(){
YMD ymd;
double t = 0.0;
#define L 9
double y[L][6] = {
{1858.0, 11.0, 17.0, 0.0, 0.0, 0.0},
{1949.0, 12.0, 31.923459, 0.0, 0.0, 0.0},
{2000.0, 1.0, 1.0, 0.0, 0.0, 0.0},
{1984.0, 1.0, 1.0, 0.0, 0.0, 0.0},
{1984.0, 1.0, 0.0, 0.0, 0.0, 0.0},
{1984.0, 12.0, 31.0, 23.0, 59.0, 60.0},
{1985.0, 1.0, 1.0, 0.0, 0.0, 0.0},
{1985.0, 1.0, 0.0, 0.0, 0.0, 0.0},
{1985.0, 12.0, 31.0, 23.0, 59.0, 60.0}
};
for(int i=0; i < L; i++){
ymdSetYear(ymd, (int)y[i][0]);
ymdSetMonth(ymd, (int)y[i][1]);
ymdSetDay(ymd, y[i][2]);
ymdSetHours(ymd, y[i][3]);
ymdSetMinutes(ymd, y[i][4]);
ymdSetSeconds(ymd, y[i][5]);
printf("%4d %2d %10.6f %10.6f %10.6f %10.6f\n", ymdGetYear(ymd),
ymdGetMonth(ymd), ymdGetDay(ymd), ymdGetHours(ymd),
ymdGetMinutes(ymd), ymdGetSeconds(ymd));
t = ymd2y(ymd);
printf("%13.8f\n\n", t);
}
return 0;
}