static int KcNgay(MyDate c)
{
int m = c.Doc_m();
int nNhuan = c.Doc_y() / 4;
int kq = 0;
do
{
if (m == 1 || m == 3 || m == 5 ||
m == 7 || m == 8 ||
m == 10 || m == 12)
{
kq += m * 31;
}
else if (m == 4 || m == 6 || m == 9 || m == 11)
{
kq += m * 30;
}
else if (m == 2 && c.KtYear(c.Doc_y()))
{
kq += 29;
}
else
{
kq += 28;
}
--m;
} while (m != 0);
kq += (nNhuan * 366 + (c.Doc_y() - nNhuan) * 365);
return(kq += c.Doc_d());
}
static void kCach(MyDate a, MyDate b, ref MyDate c)
{
c.Gan_d(a.Doc_d() - b.Doc_d());
c.Gan_m(a.Doc_m() - b.Doc_m());
c.Gan_y(a.Doc_y() - b.Doc_y());
}